Google Shopping Ads for E-commerce: Merchant Center, Feeds and Campaign Setup

Google Shopping ads show your products (image, price and store name) directly in Google results, powered by a product feed hosted in Google Merchant Center. There is no keyword list: the quality of that feed decides which searches your products appear for, which is why fixing it should come first before the holiday peak.

This guide is for e-commerce owners on Shopify, WooCommerce or any other platform who want to understand how Shopping works, avoid disapprovals and build campaigns that pay for themselves.

Key takeaways

• In Shopping, the product feed replaces keywords: titles, attributes and images drive your visibility.
• Most Merchant Center disapprovals come from a handful of known causes: price or stock mismatches, missing GTINs, incomplete business information and non-compliant images.
• Custom labels (margin, bestsellers, seasonality) let you steer budget by what actually matters to your business.
• Standard Shopping gives you control, Performance Max gives you reach: the right choice depends on your conversion volume.
• Measure ROAS by product and category, then prune whatever spends without selling.

How Shopping ads work

When someone searches for “waterproof women’s hiking boots”, Google compares that query with the data in your feed: title, description, category, product type, brand, colour and size. If your listing matches and your bid is competitive, your product can appear in the Shopping carousel, the Shopping tab, Google Images and other surfaces.

So you do not pick the searches. You influence them through data quality, bids and negative keywords. A vague title or a missing attribute is a search you will simply never show up for.

If you sell in Europe, there is one extra layer: across the European Economic Area, Shopping ads are served through a Comparison Shopping Service (CSS). By default that is Google Shopping itself, but partner CSSs exist, and they are worth evaluating for accounts with steady Shopping spend.

Setting up Merchant Center and avoiding common disapprovals

Setup always follows the same steps:

1. create your Merchant Center account and verify ownership of your website;
2. add your business details: address, customer service contact, shipping terms and return policy;
3. import products through the Google & YouTube app on Shopify, the Google for WooCommerce extension, a file, Google Sheets or the API;
4. link Merchant Center to your Google Ads account;
5. monitor the diagnostics tab product by product.

Feed optimisation: the real lever

Titles that use your buyers’ words

The title is the single most important attribute, and it can run up to 150 characters. Put the decisive information first, because the end is often cut off on screen. A structure that works for most categories: brand + product type + key attributes (material, colour, size, model). “Men’s Gore-Tex waterproof jacket, navy, size M” beats “Explorer Jacket” every time.

Identifiers, images and attributes

• GTIN, brand and MPN: they help Google match your offer to the right product and compare it.
• Images: a sharp main image on a light background, then additional images (worn, in context, details).
• Category and product type: Google assigns a product category automatically, but your own product type hierarchy remains invaluable for structuring campaigns.
• Variant attributes: colour, size, material, gender and age group, essential in fashion and strongly recommended elsewhere.

Custom labels

Merchant Center gives you five custom labels (custom_label_0 to custom_label_4) that shoppers never see. Use them to segment campaigns by your own business criteria:

If your platform makes these fields hard to edit, Merchant Center feed rules and supplemental feeds let you add them without touching the website.

Standard Shopping or Performance Max?

Worth knowing: since late 2024, when a Performance Max campaign and a Standard Shopping campaign target the same products in the same account, Google no longer gives Performance Max automatic priority; Ad Rank decides which one serves. That makes running both side by side simpler, for example Performance Max on most of the catalogue and Standard Shopping to test a specific range.

Promotions, free listings and local inventory

• Merchant Center promotions add a “special offer” annotation to your products. They go through review, so submit your Black Friday promotions several days ahead.
• Free listings are switched on by default for new accounts and show your products at no cost across several Google surfaces. They do not replace ads, but they add incremental traffic from the same feed.
• Local inventory: if you have a physical store, a local inventory feed linked to your Business Profile can show in-store availability and pickup options.

Measuring ROAS by product and pruning

A profitable Shopping account relies on reliable purchase tracking with real order values. From there, analyse performance by product, product type and custom label, and sort your catalogue into three groups:

• winners that sell at a good return: isolate them and give them more budget;
• spenders that collect clicks without selling: lower bids or exclude them once you have enough clicks to judge;
• invisibles that barely get impressions: work on their titles and attributes first.

Think in margin, not just revenue. Your break-even ROAS is simple to calculate: 1 divided by your margin rate. With a 40% gross margin, you need a ROAS of at least 2.5 (250%) just to cover the cost of clicks, before fixed costs. Fast, complete product pages are part of the equation too: a high-performing e-commerce website improves both conversion rates and product approval.

To see how we run Shopping and Performance Max campaigns day to day, explore our Google Ads management service.

Get your feed audited before the holidays

A well-structured feed can transform the profitability of a Shopping account. Adsflow offers a free audit of your Merchant Center and campaigns: disapprovals, title quality, structure and conversion tracking. One of our specialists reviews it personally and hands you clear priorities. Request your free audit.