The biggest Meta ads mistake is not installing the Meta pixel. Without the pixel, Meta cannot track conversions, optimize delivery, or build retargeting audiences. Install the pixel day one and verify it fires correctly on your website.

The second major mistake is mismatch between ad promise and landing page. If your ad says "Get a quote in 60 seconds" but your landing page has five form fields, visitors bounce. Match the promise exactly and reduce friction. One-field forms outperform everything.

Creative fatigue kills performance silently. Running the same ad for three weeks drops click-through rates by 30-40%. Rotate creatives weekly with at least 10 versions prepped. Frequency cap at 2-3 per week to prevent over-exposure that wastes budget.

Other common mistakes: ignoring iOS tracking limits, choosing the wrong campaign objective, not A/B testing, skipping retargeting, having too broad audiences, and not tracking ROAS. Launch parallel ad sets with different angles, kill losers after 7 days, and scale winners aggressively.