Top 10 Merchant Centre Optimisations for Shopping Campaigns

Most of the effort spent "optimising Shopping campaigns" happens in Google Ads — tweaking bids, excluding placements, rearranging product groups. That's the wrong end of the lever. In Shopping, the feed is the campaign. The Merchant Centre is where 70% of the actual optimisation work lives, and most accounts treat it like a static data dump.

This is the list of the ten Merchant Centre optimisations that consistently produce the biggest lift on Shopping performance — ranked roughly by impact. Do these, and your Shopping campaigns will out-perform most of your category before you've touched a bid.

1. Product Titles (The Single Biggest Lever)

Product titles in your Merchant Centre feed are what Google's algorithm matches against user search queries. A poorly-structured title means your products show for the wrong searches, or don't show at all. A well-structured title puts you in front of high-intent buyers consistently.

The ideal title structure (by category)

• Apparel: Brand + Gender + Product Type + Attributes (colour, material, size) + Style
  Nike Women's Running Trainer Air Zoom Pegasus 40 Pink Size 7
• Electronics: Brand + Model + Product Type + Key Specs
  Apple iPhone 15 Pro Max 256GB Natural Titanium Unlocked
• Home/Furniture: Brand + Product Type + Key Attribute + Material/Colour
  IKEA Malm Queen Bed Frame White Ash Veneer
• Food/Beverage: Brand + Flavour/Variant + Product Type + Size/Quantity
  Lavazza Crema e Gusto Ground Coffee 250g

Rules for high-performing titles

1. Front-load the most important keywords. Google weights the first 70 characters most heavily, and mobile search results truncate around the 70-character mark. Brand + product type should always appear in the first half.
2. Use the language customers use, not internal SKU names. Your PIM might call it "Pegasus40-W-PNK-7" — Google needs "Women's Running Trainer Size 7".
3. Don't keyword-stuff. Duplicate attributes ("Running Shoes Trainers Jogging Sneakers") trigger disapprovals and tank Quality Score. One clean, descriptive title beats a keyword soup.
4. Include size/colour variants in the title, not just as attributes. Variant-level titles (size 7, pink) win searches that variant-less competitors miss.

Fixing titles alone routinely produces 20-40% lift in impressions and 10-25% lift in click-through rate across the accounts we take over. It's the cheapest, highest-leverage optimisation in Merchant Centre.

2. Image Quality and Variants

The image is what stops the scroll. In a Shopping result grid, your product is competing with 20 others on a screen — the image is doing 80% of the work convincing someone to click. Poor imagery is a silent tax on your CTR.

Image standards that win

• Minimum 800x800px for apparel, ideally 1200x1200px or larger. Small images lose the visual competition even when the product is better.
• White or transparent backgrounds for the main image (required by Google for most categories). Lifestyle shots go in the additional_image_link fields.
• Full product visible, centred, no cropping of important details. Shoes with the toe cut off, bags with the handle clipped — all disapproval risks.
• No promotional text, watermarks, or graphics overlaid. "SALE!" banners on images are a guaranteed disapproval. Promotions go in the merchant promotions section.
• Multiple images via additional_image_link: you can submit up to 10 additional images. Use them. Side views, detail shots, in-use shots, scale references. More images = more engagement in the product viewer when users click.

The image test

Take your product image. Shrink it to 200x200px in a browser. Can you still tell what it is? Does it still look premium? If not, your image isn't working at actual Shopping-grid size. Re-shoot or re-composite.

3. Product Descriptions (More Important Than You Think)

Descriptions don't show in the Shopping grid, but they absolutely influence which queries trigger your ads — especially for long-tail searches. Google's matching algorithm parses descriptions for context the title can't fit.

What makes a good Shopping description

• First 160-200 characters carry the weight. Put the product's core value and key attributes in the opening. That's what Google reads most aggressively and what snippets pull from.
• Include synonyms and natural-language phrases. "Waterproof running jacket" and "rain-resistant running coat" both matter. Natural phrasing beats keyword-stuffing.
• Cover the questions customers ask. Material composition, care instructions, sizing notes, compatibility, warranty. If someone has to leave your page to ask a pre-purchase question, you've likely lost them.
• Keep HTML out of descriptions. Shopping strips HTML; unstripped markup looks unprofessional in some surfaces and can cause disapprovals.
• Minimum 500 characters, ideally 1,000-2,000. Thin descriptions limit how much query context Google can extract.

4. GTINs, MPNs, and Product Identifiers

Product identifiers are how Google confirms what your product actually is — and how it matches your listing to known products in its catalogue. Missing or invalid identifiers are one of the most common reasons Shopping performance underperforms expectations.

What you need

• GTIN (Global Trade Item Number): UPC, EAN, JAN, ISBN depending on region. Required for any product with a manufacturer-assigned code. This is the single most important identifier for reach.
• MPN (Manufacturer Part Number): required if GTIN is unavailable but the brand is known.
• Brand: always include; even generic products should have a brand (your own store brand is acceptable).
• For custom or handmade products: set identifier_exists to false to tell Google no GTIN exists. Don't leave it blank.

Accounts missing GTINs on products that should have them routinely see 20-40% fewer impressions than identical accounts with correct identifiers. This is free reach you're leaving on the table.

5. Google Product Category (Get It Right)

The google_product_category field tells Google's taxonomy exactly what type of product this is. It affects which Shopping surfaces your product appears on, what competitive set Google places you in, and how bids compete.

The specificity rule

Always use the most specific category available. Google's taxonomy goes 5-6 levels deep — use all of them. For example, don't stop at Apparel & Accessories (Level 1). Go to Apparel & Accessories > Clothing > Activewear > Running > Running Trainers. Generic categories get lumped into generic auctions; specific categories compete in the right micro-auction.

You can use either the numeric category ID or the full path string. Numeric is less error-prone. Google publishes the full taxonomy as a downloadable file — map your product types to the taxonomy once, reference it on every feed upload.

6. Custom Labels (Campaign Segmentation Superpower)

Custom labels (custom_label_0 through custom_label_4) are invisible to shoppers but critical for campaign structure. They let you segment products for different bid strategies, budget allocation, and reporting without restructuring your feed.

The custom label framework I use

Label	Purpose	Example Values
custom_label_0	Margin tier	high_margin, mid_margin, low_margin
custom_label_1	Performance tier	best_seller, top_20pct, new_product, clearance
custom_label_2	Price bracket	under_50, 50_to_150, over_150
custom_label_3	Seasonality	year_round, summer, winter, christmas
custom_label_4	Stock/strategic flag	low_stock, preorder, exclusive, core_range

With this structure, you can build Shopping campaigns that bid aggressively on high-margin best-sellers, conservatively on clearance, and exclude low-stock or preorder items entirely — all via product group filters, no feed duplication needed.

7. Feed Freshness (Avoid the Silent Disapproval Trap)

Every Merchant Centre feed has an expiry. Default is 30 days; products not re-submitted within that window silently fall out of Shopping. More importantly, stale data (price mismatches, out-of-stock items still listed as in-stock) triggers disapprovals that can cascade into full account suspensions.

Feed update strategy

• Scheduled fetches every 24 hours minimum. Configure Merchant Centre to pull your feed daily. Free, automated, critical.
• Real-time updates via Content API for high-velocity attributes. Stock levels, prices, and availability should update in near-real-time on fast-moving stores. Shopify / WooCommerce / Magento integrations typically handle this; if you're on a custom stack, Content API integration is worth the build effort.
• Automatic item updates: enable this in Merchant Centre so Google can update price and availability from your website's structured data if the feed lags. Safety net, not primary mechanism.
• Price and availability microdata on product pages. Required for automatic item updates to work. Validate with Rich Results Test.

8. Merchant Promotions and Sale Price

Promotions make your product visually stand out in Shopping results with a "Special Offer" badge or a strikethrough price — both proven to lift CTR by 10-30%. Most accounts underuse this feature because setup isn't obvious.

Two mechanics to know

1. Sale price attribute: include sale_price and sale_price_effective_date in the feed. Google shows the strike-through automatically when the feed is submitted correctly. No separate promotion upload needed.
2. Merchant promotions: separate submission for coupon codes, free shipping, percentage-off deals. These show as a clickable "Special offer" on the ad. Requires enabling the Promotions programme in Merchant Centre first, then uploading promotion data (via feed or API).

Rules to follow

• Sale price must be meaningfully lower than the base price (at least 5%; deeper discounts preferred).
• Sale price cannot have been the base price for a significant part of the past 30 days (anti-fake-discount rule — Google is strict here and getting stricter).
• Promotion codes must actually work at checkout. Google will disable promotions that customers can't redeem.

9. Product Ratings and Reviews

Star ratings next to a Shopping listing lift CTR by 10-25% consistently. They're the single most valuable visual element on a listing after the image itself. Getting them integrated properly is a one-time setup that pays out every day thereafter.

Two paths to ratings

1. Google Customer Reviews: free, native Google programme. Customers get an email after purchase asking to rate the purchase experience and optionally the product. Ratings flow into your Shopping results automatically. Minimum threshold applies (usually 50+ reviews across the store).
2. Third-party review platform: Trustpilot, Feefo, Yotpo, Reviews.io, Bazaarvoice, and a few others are Google-approved review aggregators. They push product review data to Google, which then surfaces it on Shopping listings. Typically the faster path for established stores that already use a review platform.

Product-level reviews (not just store-level) are the ones that appear on Shopping listings. Make sure whichever system you use is capturing per-product reviews with the correct product IDs tied to your feed.

10. Disapproval Monitoring and Policy Compliance

The most damaging Merchant Centre problem isn't a bad feed — it's a feed with disapprovals you don't know about. A single policy violation can silently remove thousands of products from Shopping, or in severe cases, suspend your Merchant Centre account entirely. Monitoring is non-negotiable.

What to monitor weekly

• Diagnostics dashboard in Merchant Centre: shows all disapproved and warned items by reason.
• Account-level issues: "misrepresentation", "shopping ads policy", and similar issues are existential. They can trigger full account suspension. Escalate immediately.
• Item-level issues: price mismatches, missing shipping, image problems, GTIN errors. Fix in the feed, not via manual overrides (which don't persist).
• Warnings: not yet causing disapproval but will eventually. Ignoring warnings is how stores end up with 40% of their catalogue disapproved overnight.

The most common disapprovals and how to fix them

1. Mismatched price / availability — feed says £49.99 but the product page shows £54.99. Fix: real-time feed sync or automatic item updates.
2. Missing shipping / tax — required for any product being sold, even if it's £0 (free shipping). Configure in account settings, not just feed.
3. Image issues — promotional overlays, placeholder images, low resolution. Re-upload clean main images.
4. Inappropriate content / restricted products — alcohol, pharmaceuticals, certain categories need specific approvals. Make sure your account is certified for your vertical.
5. Landing page issues — product page 404s, redirect loops, mobile unfriendliness. Fix on-site, not in the feed.

Policy compliance basics

• Comprehensive returns and refund policy visible on every product page.
• Clear contact information — phone number or live chat plus email. "Contact form only" triggers issues.
• Secure checkout (HTTPS end-to-end, not just HTTPS on checkout).
• Terms and conditions, privacy policy, cookie consent all present and accurate.
• No misleading claims on product pages (e.g. "lowest price guaranteed" without substantiation).

How to Prioritise These 10 Optimisations

Most accounts can't do all ten at once. If you're starting from scratch, here's the order that produces the biggest ROAS lift fastest:

1. Disapprovals first. Before optimising anything, make sure your products are actually eligible to show. A perfect title on a disapproved product is worth nothing.
2. Product titles. Single biggest lever. Audit and rewrite structure on the top 20% of products first — that's usually 80% of the revenue.
3. GTINs and identifiers. Quick, high-impact, one-time fix.
4. Images. Re-shoot or re-composite the main images on your top sellers. Cheap lift.
5. Custom labels. Builds the foundation for proper campaign structure downstream.
6. Feed freshness. Set up daily fetches and real-time price/availability syncing.
7. Descriptions. Rewrite for the top sellers once titles are clean.
8. Product ratings. One-time integration; pays out for years.
9. Promotions / sale price. Layer in during sales cycles.
10. Google product category. Refine to the deepest specific level across the catalogue.

Most agencies spend 90% of their time tweaking Google Ads and 10% on the feed. The best Shopping specialists flip that ratio. If the feed is clean, structured, and complete, the campaigns almost optimise themselves.

If you're running Shopping without tight control over these ten areas, you're leaving significant revenue on the table. The good news is this is all structural work that compounds — fix it once, benefit from it every day thereafter. For context on how feed structure interacts with campaign choice, it's worth pairing this with our comparison of Performance Max vs Standard Shopping and our full Google Ads audit checklist.