Biggest mistakes I see in accounts:
– smart bidding without enough conversions
– not segmenting, normally for Pmax in bigger accounts
– too much segmenting, SKAG style
– not measuring Product ID, needed for remarketing products
– not tracking interesting conversions (added products, start payment, etc.)
– not using the Ads tag
– using broad match without understanding the reach
– having brand in Pmax
– not using scripts for extra insights
– bad ad copy
– using optimized targeting in remarketing
– not having a clear goal
– not using enhanced conversions, offline conversion tracking, or call tracking
I definitely miss some mistakes but these were top of mind.
