Judging every format by the same metric
Holding a Display awareness campaign to the same CPA target as a Search retargeting campaign guarantees disappointment — match the metric to the objective (impressions/reach for awareness, CPA/ROAS for conversion) before you even launch.Metric mismatch
Turning campaigns off before they exit the learning phase
Most auction-based platforms need a meaningful volume of conversions (commonly 50+) before their delivery algorithm stabilizes — killing a campaign after two quiet days almost always throws away data right before performance would have improved.Too impatient
Reusing one creative across every platform, unedited
A polished 30-second TV-style ad dropped straight into TikTok's feed reads as an ad instantly and gets scrolled past — each platform's native creative grammar (covered throughout this guide) genuinely changes what performs.Wrong native format
Ignoring frequency caps until an audience is visibly fatigued
Engagement and sentiment both decline once the same person has seen an ad too many times — set a frequency cap deliberately instead of discovering the ceiling from declining CTR after the fact.Ad fatigue
Targeting too broadly, then blaming the format
A format rarely underperforms in isolation — an audience that's too broad, too cold, or mismatched to the offer usually explains a disappointing result better than "this platform doesn't work for us."Audience mismatch
Never testing more than one creative at a time
Without an A/B test running, there's no way to separate a genuinely weak format choice from simply weak creative — and the two get confused constantly, leading advertisers to abandon formats that would have worked with better assets.No testing