How to set up Google Ads for ecommerce, step by step

How do you set up Google Ads for ecommerce?

An ecommerce Google Ads setup has five layers, and the order matters: purchase conversion tracking, Merchant Center and your product feed, a Shopping or Performance Max campaign, a brand search campaign and negative keywords. If you start spending before measurement works, smart bidding learns from the wrong signals and your budget is wasted.

Below we go through each step along with the mistakes we see most often in online stores. If your account already exists, use this order as an audit checklist.

What should be ready before you start?

Before opening campaigns, sort out the following:

• A target ROAS or target CPA. Without a target derived from your margins, you cannot tell whether a campaign is working.
• Site readiness. Real contact details, return and shipping policies and a secure checkout. You need these for Merchant Center approval and for conversion rate.
• Access. Your company should own the Google Ads, Google Analytics, Merchant Center and Google Tag Manager accounts, and grant admin access to any agency or freelancer rather than the other way round.

Step 1: How do you set up purchase conversion tracking?

In Google Ads, a conversion is a valuable action a user completes after interacting with your ad. In ecommerce the main conversion is the purchase, and it must be sent with the order value; otherwise value-based bidding strategies cannot work.

1. In Google Ads, go to Goals > Conversions and create a website purchase conversion.
2. Install the tag through Google Tag Manager, a platform integration (such as the Google & YouTube app on Shopify) or directly in code.
3. Pass the order value, currency and transaction ID. The transaction ID prevents the same order being counted twice.
4. Mark purchase as a "primary" conversion and micro conversions such as add to cart as "secondary". Bidding only optimizes toward primary conversions.
5. Turn on enhanced conversions. According to Google, this feature improves the accuracy of conversion measurement by sending hashed first-party customer data in a privacy-safe way.
6. Place a test order and confirm the conversion appears in Google Ads.

To reduce conversions lost to cookie restrictions, see our server-side tracking guide.

Step 2: How do you prepare Merchant Center and your product feed?

Shopping ads and the product side of Performance Max are powered by your product data in Merchant Center. To run Shopping ads, your Google Ads account must be linked to a Merchant Center account.

• Create a Merchant Center account, then verify and claim your website.
• Configure shipping and return settings.
• Upload your product feed (platform app, Google Sheets or scheduled fetch).
• Fix disapproved products in the diagnostics view.
• Link Merchant Center to your Google Ads account.

Feed quality directly affects performance: titles, product type, GTINs and image quality determine which queries you appear for. Our Performance Max product feed guide gives a detailed roadmap.

Step 3: Shopping or Performance Max?

Both campaign types use the same feed but differ in control and reach:

Feature	Standard Shopping	Performance Max
Channels	Mainly Google Search and the Shopping tab	Search, Shopping, YouTube, Display, Gmail, Discover, Maps
Control	High, at product group, bid and search term level	Asset group and signal level, more limited
Automation	Manual or smart bidding	Smart bidding only
Required content	Feed only	Feed, images, text, optional video
Good fit	Tight control, small budget, clear query analysis	Enough conversion data, broad reach goals

A practical start: in accounts with conversion history, run Performance Max as the main campaign and split asset groups by category or margin. If you want more control over part of the catalog, move those products into standard Shopping.

Step 4: Why set up a brand search campaign?

When people search for your brand name, competitors can show ads on that search. A separate brand campaign:

• Protects the top position on brand searches.
• Separates brand traffic from new-customer campaigns so reports are cleaner. Because Performance Max can also capture brand searches, review brand exclusion settings.
• Lets you control promotion, discount and shipping messages in the ad copy.

Brand campaign ROAS will always look very high because these users already know you. Do not read that number as the success of the whole account.

Step 5: How do you use negative keywords?

Negative keywords stop your ads from showing on certain queries. Google notes that they help keep your ads away from people who are not interested, protecting budget. The basic lists an online store needs:

• Off-intent queries: "free", "used", "how to make", "jobs" and similar.
• Products and brands you do not sell.
• Traffic sculpting between campaigns: adding brand terms as negatives in new-customer campaigns so brand traffic flows to the brand campaign.

Review the search terms report frequently in the first weeks, then on a regular schedule, and keep the lists updated.

Which bid strategy should you start with?

The bid strategy defines what the campaign tries to maximize. Since the goal in ecommerce is order value, value-based strategies (maximize conversion value and target ROAS) are the right choice in the long run. They do, however, need enough conversion data in the account to work well.

For a new account or one with thin history, a sensible sequence is:

• Early phase: Start with maximize conversion value without a target and keep the budget under control.
• As data builds up: Add a target ROAS close to the ROAS you are actually achieving. Setting it far above real performance throttles impressions.
• Mature account: Adjust target ROAS gradually toward your margin-based goal and manage product groups with different margins in separate campaigns or asset groups.

Changing the bid strategy can send a campaign back into learning, so make changes rarely and deliberately, and watch the effect of each one for at least a few weeks.

What should you watch in the first weeks after setup?

• Compare conversion counts with orders in your store admin. If there is a big gap, fix measurement first.
• Do not change bid strategy and budget often; smart bidding needs data to learn.
• Check Merchant Center diagnostics weekly; disapproved products quietly cost sales.
• Do not set target ROAS too high from day one, or the campaign will not get enough impressions.

Key takeaways

• Measurement first: purchase tracking with value, transaction ID and enhanced conversions.
• Verify Merchant Center, configure shipping and returns, and clear feed errors.
• Use Performance Max when you have conversion data, standard Shopping when you need control.
• Keep a separate brand campaign and read its ROAS separately.
• Manage negative keyword lists from day one.

If you would like to see which of these steps your current Google Ads account is missing, you can book a free growth analysis with the Performetic team.