Bots
Firstly trade reports.... There are bots who buy crops from the market you should be able to recognise them as they can buy ally crop very fast, they can buy 2 loads of crop in one second at times, most normal players find this impossible with trade report successful notification in between.
Subs, a player suspected of using a bit will also be able to train 1/1/1/1 of each troop very quickly and not command battles. Attack them from nearby and notice how they rebuild troops and some turrets but never command the battle. Funny isn't it.
Feel free to add more if you know more methods
Nathan05
S106