Only use autoplay in battles against zombies, as AI can usually handle them properly.
You can have up to three teams active, and one of them should be crafted specifically and exclusively for defending.
When fighting the hordes of zombies, it’s best to try and attack/destroy the closest ones first, then the ones in the back: the closest zombies will move in fast.
You should aim at not having more than 15 characters at any given time, and always choose upgrading the rarest one first.
Don't claim rewards until you actually need them, as they can't be stolen from the missions/achievements tab. Store them there and claim them when there is a need.
Survivors have four different traits, and they are marked with different colors. Blue beats red, red beats green, green beats yellow, and yellow beats blue.
You can get free coins by going to the IAP menu and either watching ads or complete offers.