Cheating at golf is very common among recreational players. A common trick is to move your ball onto the edge of the fairway when nobody is looking.
“Improving your lie” is a common way, meaning altering the environment around the player, swing path, ball, or shot path in a way that yields some advantage.
This would include things like breaking off a twig in your way, removing leaves or grass around the ball, etc.
Mostly things like illegal equipment (besides blatantly breaking rules).