Most Google Ads optimization advice focuses on surface-level tweaks — add negative keywords, adjust bids, test ad copy. These things matter but they're not where the biggest leverage is. The biggest improvements come from fixing structural issues in how campaigns are set up and measured. This guide focuses on the changes that actually move the needle.
Audit Your Conversion Tracking First
Everything in Google Ads optimization depends on accurate conversion data. If your purchase events aren't firing correctly, Google's algorithm is optimizing for the wrong thing — and no amount of bid adjustment or audience refinement will fix that. Before touching anything else, compare your Google-reported conversions against your actual Shopify orders for the same period. They should be within 10-15% of each other. A larger gap means a tracking problem.
Check that you have Enhanced Conversions enabled, that your conversion value (revenue) is being passed correctly with each purchase event, and that you're not double-counting conversions by having both the Google tag and Shopify's built-in Google channel firing for the same events.
Fix Your Product Feed
For Shopping campaigns, the quality of your product feed is more important than your bids. Google uses your feed data — product title, description, category, price, images — to match products to search queries. A poorly optimized feed means your products show up for the wrong searches (wasted spend) and miss the right ones (lost revenue).
Start with product titles. Include the most important search terms in the title naturally: brand, product type, key attributes like color and size. Then review your product categories — make sure you're using the most specific Google Product Category for each item. These two changes alone often improve Shopping campaign performance significantly.
Add Negative Keywords Systematically
For Performance Max and Shopping campaigns, Google will sometimes show your products for irrelevant searches that eat budget without converting. Go to your Search Terms report weekly and add irrelevant queries as negatives. Common examples for ecommerce: competitor brand names (unless you want to bid on them intentionally), DIY terms for products you sell ready-made, and informational queries without purchase intent.
Build a negative keyword list over time and apply it across campaigns. This is ongoing work but it compounds — every irrelevant term you block improves the efficiency of your remaining spend.
Set the Right Bidding Target
Target ROAS bidding is powerful but commonly misconfigured. The target you set needs to be achievable — if you set a target that's too high, Google can't find enough traffic to spend your budget and performance degrades. A good starting point is your actual average ROAS from the last 30 days, then incrementally increase it as campaign performance improves.
Make sure your ROAS target is set based on realistic business needs, not based on what Google's platform reports. If your break-even ROAS is 2.5x and you're consistently hitting 4x, you have room to either scale budget or push for higher efficiency. If you're barely hitting break-even, something else needs to change before chasing higher targets.
Prioritize High-Margin Products
Google treats all products equally unless you tell it otherwise. If you have products with dramatically different margins, use campaign priority settings or separate campaigns to direct more spend toward high-margin items. A campaign structure that reflects your product margin hierarchy will outperform a flat structure where everything competes for the same budget.
Measure Beyond the Google Dashboard
Google's dashboard shows you Google's attributed performance. To understand Google's actual contribution to your business, you need to look at blended ROAS — how does your total Shopify revenue change as a function of your Google spend? Metricx connects your Google Ads data with your real Shopify orders so you can see this clearly. Try it free.