We audit dozens of Google Ads accounts every month. The same seven mistakes show up in 90% of them — and fixing them typically cuts CPA by 30-50% within a single quarter. None of these require advanced strategy. They require knowing where Google’s defaults will quietly burn your money, and choosing the smarter setting instead.

Google Ads is the most powerful demand-capture channel in the world. It’s also designed to spend your budget as fast as possible. Most account defaults favor Google’s revenue, not yours. This article walks through the seven traps we see most often, why Google nudges you into them, and the exact settings to change.

Mistake 1: Using broad match by default

When you create a new keyword, Google defaults to broad match. The wizard interface barely shows you the alternatives. Broad match means “show this ad for anything Google’s AI thinks is related” — including searches that have almost nothing to do with your business.

Mistake 2: No negative keywords

Without negatives, you’re paying for clicks from people who will never buy. Examples: a $200/night hotel paying for “free hotel coupon” searches. A $5K SaaS paying for “free alternative” searches. A premium service paying for “cheap” searches.

A startup negative keyword starter list

Add these as account-level negatives on day one (adjust to your category):

• free, cheap, discount, coupon — unless you’re running deals
• jobs, career, salary, hiring — if you’re not recruiting
• diy, tutorial, how to — if you sell done-for-you
• vs, alternative, review — if you’re not the brand being compared
• refund, complaint, scam — protect from reputation searches

Mistake 3: Letting Performance Max cannibalize brand traffic

Performance Max (PMax) is Google’s newest campaign type and the one their reps push hardest. It runs across Search, Display, YouTube, Shopping, and Discover automatically. Sounds great — except by default PMax will happily eat your budget on people searching your brand name (cheap clicks, easy “conversions” that would have happened organically anyway).

Mistake 4: One ad per ad group

Running a single Responsive Search Ad (RSA) per ad group is a missed test opportunity. Google rewards accounts with 2-3 RSAs per ad group with more impressions and lower CPCs (the auction prefers accounts that give the algorithm options to choose from).

Mistake 5: Ignoring conversion tracking

This is the single most common mistake we find. Smart bidding (Maximize Conversions, Target CPA, Target ROAS) is only as good as the conversion data feeding it. If tracking is broken, the algorithm is optimizing against noise — and your CPA will be 2-3× what it should be.

Mistake 6: No ad extensions (now “assets”)

Sitelinks, callouts, structured snippets, lead form extensions, image assets, price assets — all FREE additional real estate on the search results page. Accounts with all relevant asset types stacked get 10-20% higher CTR than accounts running plain text ads. That CTR improvement directly improves Quality Score, which lowers your CPC.

Mistake 7: Optimizing daily for the first 14 days

Smart Bidding needs 30-50 conversions of data before it exits the “learning” phase. Daily tweaks — changing bids, pausing keywords, adjusting budget — reset the learning phase and waste the spend you already paid for. The temptation is real (“CPA looks bad, let me fix it!”) but the discipline of leaving the campaign alone for 14 days is what separates good media buyers from average ones.

Bonus mistake 8: Wrong bidding strategy for your stage

Most startups start with “Maximize Clicks” because it spends budget reliably. Wrong choice. Maximize Clicks optimizes for clicks, not conversions — so you get traffic but not customers. Here’s the right bidding strategy for each stage:

What to audit in your account this week

Google Ads rewards patience and good tracking — not constant tinkering.