Google Shopping Ads: How to Set Up and Optimise for E-commerce

Why Shopping Ads Work

Shopping ads show a product image, title, price, store name, and sometimes reviews right in the search results. Before a user clicks, they already know what the product looks like and how much it costs. That pre-qualification is why Shopping ads consistently deliver higher conversion rates and lower cost per acquisition than text ads for e-commerce.

Think about the difference. A text ad says ‘Buy Running Shoes Online — Free Delivery’. A Shopping ad shows the exact shoe, in the exact colour, at £89.99, with 4.5 stars from 200 reviews. The user clicking the Shopping ad is much further along in the buying journey. They’ve already decided they like the look of it and the price works. That click is worth significantly more.

Shopping ads also take up more visual real estate in search results. Google typically shows 4–8 Shopping results in a carousel at the top of the page, above text ads. That visibility drives volume. For most e-commerce businesses, Shopping should be the primary campaign type, with text ads playing a supporting role.

The Setup: Merchant Center and Product Feed

Google Merchant Center

Before you can run Shopping ads, you need a Google Merchant Center account. This is where Google stores your product data. Think of it as a database of everything you sell — every product, variant, price, and image.

Setting it up is straightforward:

1. Go to merchants.google.com and create an account
2. Verify and claim your website URL
3. Set up your shipping settings (Google uses these to show accurate delivery info)
4. Set up your tax settings if applicable
5. Link your Merchant Center to your Google Ads account

The linking step is critical. Without it, your product data can’t be used in ad campaigns. Go to Settings > Linked accounts in Merchant Center and connect your Google Ads account.

The product feed

The product feed is the file that tells Google everything about your products. It’s the single most important element of Shopping ads. A bad feed means bad ads, regardless of how well your campaigns are structured.

Here are the essential feed attributes you need to get right:

• Title: The product name as you want it to appear in ads. This is the most important attribute for matching to search queries. Include key details like brand, product type, colour, size, and material. Google uses the title to decide when to show your product.
• Description: A detailed product description. Include relevant keywords naturally, but write for humans. Google uses this for matching but doesn’t show it in the ad itself.
• Images: High-quality product images on a white background. No watermarks, no promotional text, no logos overlaid. Google is strict about image requirements and will disapprove products that don’t comply. Your main image should show the product clearly, ideally filling 75–90% of the frame.
• Price: The current selling price, matching exactly what’s on your website. Any mismatch between your feed price and landing page price will get the product disapproved. If you run sales, use the sale_price attribute alongside the regular price.
• GTIN (Global Trade Item Number): The barcode number for your product — EAN, UPC, or ISBN depending on your region. Google strongly prefers products with GTINs because it can match them to its product catalogue. Products with GTINs typically get more impressions.
• Google product category: Google’s taxonomy for classifying products. Be as specific as possible. ‘Apparel & Accessories > Clothing > Dresses’ is better than just ‘Apparel’. Google can auto-categorise, but doing it yourself gives you more control.
• Availability: In stock, out of stock, or preorder. Keep this synced with your website. Advertising out-of-stock products wastes money and frustrates customers.

If you’re using Shopify, WooCommerce, or BigCommerce, there are plugins that generate and sync your feed automatically. For Shopify, the Google & YouTube app handles this. For WooCommerce, plugins like Product Feed PRO work well. These save enormous amounts of time compared to managing a feed manually.

Performance Max: The New Normal

How PMax works for Shopping

Google has been pushing advertisers from standard Shopping campaigns to Performance Max (PMax) since 2022. PMax uses your product feed but shows ads across all Google surfaces — Search, Shopping, Display, YouTube, Gmail, Discover, and Maps. The algorithm decides where to show which products based on performance signals.

For most advertisers, PMax has replaced standard Shopping entirely. Google no longer lets you create new standard Shopping campaigns in some account configurations. Whether you like it or not, PMax is where Shopping is heading.

The benefit of PMax is reach — your products can appear anywhere across Google’s network. The downside is control — you can’t see exactly where your budget is going or which placements are driving results. Google gives you aggregate data, not channel-by-channel breakdowns.

Making PMax work

PMax with Shopping works best when you give the algorithm clear signals:

• Use asset groups strategically. Don’t dump all products into one asset group. Segment by product category, margin, or performance level. This lets Google optimise each group independently.
• Provide strong creative assets. PMax needs images, headlines, descriptions, and ideally video. The more assets you provide, the more combinations Google can test. But quality matters — bad creative across more placements just means bad ads everywhere.
• Set audience signals. Tell Google who your customers are. Upload customer lists, add remarketing audiences, and specify in-market and affinity segments. These are signals, not targeting restrictions — Google can go beyond them, but they help the algorithm start in the right place.
• Use value-based bidding. For Shopping, maximise conversion value or target ROAS gives Google the signal to prioritise high-value products and high-intent shoppers. Maximise conversions treats a £5 sale the same as a £500 sale, which is rarely what you want.
• Exclude branded search. PMax will happily spend your budget on branded searches where you’d rank organically anyway. Create a brand exclusion list to prevent this and keep PMax focused on new customer acquisition.

Standard Shopping (If You Can Still Run It)

If your account still supports standard Shopping campaigns, they offer significantly more control than PMax. You can set bids by product group, see search term data, and control exactly where your budget goes.

Standard Shopping structure typically works best with three priority tiers:

• High priority campaign: Low bids, catches broad searches. Acts as a filtering layer.
• Medium priority campaign: Medium bids, catches mid-funnel searches that pass through the high priority filter.
• Low priority campaign: Highest bids, catches the most specific, high-intent searches. This is where you make your money.

This structure uses campaign priorities and shared negative keyword lists to funnel search queries to the right campaign at the right bid. It’s more complex to set up but gives you granular control over how much you pay for different types of searches.

Feed Optimisation Tips

Title formulas by category

Your product title is the most important feed attribute for determining when your ads show. Here are proven title formulas by product category:

Clothing: Brand + Gender + Product Type + Colour + Size + Material

Nike Women’s Air Max 90 Running Shoes — White/Pink — Size 6 UK

Electronics: Brand + Product Name + Key Spec + Model Number

Samsung Galaxy S24 Ultra 256GB Smartphone — Titanium Black — SM-S928B

Home & Garden: Brand + Product Type + Key Feature + Dimensions/Size

Dulux Weathershield Exterior Masonry Paint — Pure Brilliant White — 5L

Front-load the most important information. Google truncates titles at around 70 characters in Shopping ads, so the first few words need to do the heavy lifting. If someone is searching for ‘Nike Air Max 90 white’, having ‘Nike’ and ‘Air Max 90’ at the start of your title is more important than any other detail.

Custom labels for segmentation

Custom labels let you tag products with your own attributes for campaign segmentation. You get five custom labels (custom_label_0 through custom_label_4). Use them strategically:

• Margin tier: High margin, medium margin, low margin. Bid more aggressively on high-margin products.
• Seasonal: Summer, winter, evergreen. Adjust bids and budgets based on seasonality.
• Best sellers: Top 20%, mid-tier, long tail. Give your proven winners more budget.
• Price range: Under £25, £25–100, over £100. Different price points often need different bidding strategies.
• New arrivals: Tag new products so you can give them dedicated budget and monitoring during launch.

Supplemental feeds

Supplemental feeds let you add or override data in your primary feed without modifying the primary feed itself. This is incredibly useful for:

• Optimising product titles without changing them on your website
• Adding custom labels when your e-commerce platform doesn’t support them natively
• Fixing disapproved products by providing missing attributes
• Adding promotional pricing or sale information

Create a supplemental feed in Google Sheets, link it to your Merchant Center account, and it merges with your primary feed automatically. This is the easiest way to optimise titles at scale without touching your website.

Common Shopping Mistakes

1. Ignoring product disapprovals. Check your Merchant Center diagnostics regularly. Disapproved products don’t show in ads, and if too many products are disapproved, Google can suspend your entire account. Common reasons: price mismatches, missing GTINs, image policy violations, and landing page issues. Fix them promptly.

2. Using manufacturer default titles. The title your supplier gives you is almost never optimised for search. ‘SKU-12345-BLK’ means nothing to Google or to shoppers. Rewrite titles using the formulas above. This single change can dramatically improve impressions and click-through rates.

3. Low-quality images. Your product image is the first thing shoppers see. Blurry photos, cluttered backgrounds, lifestyle shots as the main image, or images with promotional overlays all hurt performance. Invest in clean, professional product photography on white backgrounds. It pays for itself many times over.

4. Not segmenting by performance. Treating all products equally means your best sellers subsidise your worst performers. Segment products by performance, margin, or category and allocate budget accordingly. Your top 20% of products likely drive 80% of revenue — make sure they’re getting enough budget.

5. Advertising out-of-stock products. Every click on an out-of-stock product is wasted money and a frustrated potential customer. Set up automatic feed rules to exclude products when inventory drops to zero. Most feed management tools can do this automatically.

6. Not using negative keywords. In standard Shopping campaigns, you can’t choose which searches trigger your ads, but you can exclude irrelevant ones. Check your search terms report weekly and add negatives for searches that don’t match buying intent. In PMax, you can now add account-level negative keywords — use them.