The essentials
- The situation: in the accounts audited by GreenRed, 20 to 40% of the budget goes on unrelated or out-of-area queries, because of three settings left on their defaults.
- The costliest mistakes: conversions not measured, broad match with no negative keywords, “presence or interest” geographic targeting, Display Network enabled on a Search campaign.
- Verification: the Search terms report, the campaign settings and the Conversions tab are enough to detect nine mistakes out of ten.
- The gain: fixing these mistakes often brings the cost per conversion down by 20 to 50% without raising the budget.
Google Ads is designed to spend the budget you give it, not to spend it well. The default settings favour volume, and the mistakes that follow are found in most of the SME accounts audited. Each one is described with its cost, how to spot it and the fix.
The ten mistakes in one table
| # | Mistake | Typical cost | Where to see it |
|---|---|---|---|
| 1 | No conversion tracking, or false conversions | Steering blind; automated bidding unusable | Tools > Conversions |
| 2 | Broad match with no negative keywords | 20 to 40% of the budget on off-topic queries | Search terms report |
| 3 | “Presence or interest” targeting instead of “presence” | Clicks from other regions or countries | Campaign settings > Locations |
| 4 | Display Network or search partners enabled on a Search campaign | Low-intent clicks, conversion rate divided by 3 to 5 | Settings > Networks |
| 5 | A single ad per group, with no variants or assets | Low click-through rate and Quality Score, higher CPC | Ads and assets |
| 6 | Generic landing page (home page) | Low conversion rate, degraded Quality Score | Landing page column |
| 7 | Catch-all ad groups (30 unrelated keywords) | Ads with little relevance, high CPC | Account structure |
| 8 | Automated bidding launched with no conversion history | Endless learning phase, erratic CPA | Bid strategy |
| 9 | Budget spread across too many campaigns | No campaign gets out of learning | Campaigns view |
| 10 | Account never reviewed: recommendations applied automatically | Unwanted expansions, keywords added by Google | Recommendations > Auto-apply |
Mistake 1: not measuring conversions
Without reliable conversions, there is no way to know which keyword, which ad or which area pays off. The accounts concerned optimise on clicks or click-through rate, which amounts to paying for traffic. Define the actions that matter (form, call, purchase, appointment booking), measure them with the Google tag or the GA4 import, and exclude “noise” conversions (page views, menu clicks). The method is in Google Ads conversions.
Mistakes 2 to 4: the default settings that widen delivery
- Broad match: Google delivers on “related” queries as it interprets them. Without an exclusion list built every week from the Search terms report, a plumber pays for clicks on “plumbing course” or “plumber salary”. Match types are explained in understanding keyword match types.
- Presence or interest: the default setting includes people who are “interested in” your area, including from abroad. Switch to “Presence: people in your targeted locations”.
- Display and partners: a Search campaign created quickly often has the Display Network ticked. Display clicks cost less but rarely convert; untick it, and create a separate Display campaign if the need exists.
Mistakes 5 to 7: relevance, and therefore the cost per click
Google charges less for relevant ads: the Quality Score weights the bid. A single ad with no variants, a home page as the destination and mixed ad groups degrade this score and push the CPC up by 20 to 60%. The fix: groups of 5 to 15 closely related keywords, a responsive search ad with 10 to 15 headlines and 4 descriptions that pick up the group’s keywords, assets (sitelinks, callouts, snippets) and one landing page per group that answers the query. The organisation is described in structuring a Google Ads account.
Mistakes 8 and 9: bidding and budget
Automated strategies (target CPA, target ROAS, maximise conversions) need 30 to 50 conversions per month per campaign to learn. Launching them on a campaign with 5 conversions a month produces CPAs that double from one week to the next. Start with manual CPC or capped “maximise clicks”, then switch to automated once the history exists; the thresholds are in automated bidding. The same logic applies to the budget: three campaigns at €10 a day never learn; one campaign at €30 does.
Mistake 10: letting Google steer
The Recommendations tab suggests broadening keywords, switching to broad match, raising budgets. Auto-applying these recommendations can be enabled in one click, and is sometimes switched on by a Google sales rep over the phone. The result: keywords added without validation and rising spend. Turn off auto-apply and handle recommendations one by one, refusing those that widen delivery without evidence. A regular account audit is described in what a good SEA audit should contain.
The routine that avoids these mistakes
- Every week: Search terms report, adding exclusions, checking conversions.
- Every month: ads (weak variants to replace), Quality Score by keyword, budget split, CPA by campaign and by area.
- Every quarter: full audit of settings and structure, comparison against objectives; the metrics are in the Google Ads KPIs.
How GreenRed helps
Rather than juggling several tools, GreenRed's Google Ads module brings these metrics together in a single dashboard, compares them over time and tells you which actions come first. You can try it free, with no card, from the Pricing.
Frequently asked questions
What is the costliest Google Ads mistake?
The lack of conversion tracking. Without it, all the other mistakes stay invisible and automated bidding cannot work. It is fixed in a few hours with the Google tag or by importing GA4 key events.
Should you refuse all Google Ads recommendations?
No, but handle them one by one. Those that fix disapproved ads, add assets or flag negative keyword conflicts are useful. Those that widen delivery (broad match, new keywords, budget increases) should be validated by your conversion data, not by the optimisation score.
How many negative keywords do you need?
There is no target number. A healthy account adds exclusions every week from the Search terms report, and has a shared list of generic exclusions (free, jobs, training, reviews, definition) applied to every campaign. Several hundred exclusions after a year is common.
How can I tell whether my account has these mistakes without expertise?
Three checks in ten minutes: does the Conversions tab contain a primary action with recent conversions; do the campaign settings say “Presence” and Search only; does the Search terms report mostly contain queries from potential customers. An SEA audit formalises this check.