If you want to know how to play petville properly, then you’ll need a good petville guide that shows you what to do. And let me make one thing clear: cheats are not the answer! In fact there are no real working cheats for the game out yet that will just magically make you win. But there are legitimate tactics that will have you easily beating all your friends, without too much effort.
Right now I do not know of any really good guides out on the market, so check back here later to see if things have changed. Good luck playing petville until then.