You don't have to be good at the pet games in order to gain sufficient pet experience. Simply use snacks you have gained or bought and feed them to your pet upon completion of every game. If your pet either likes it or loves it, the experience you gain for your pet will increase more. The Snack Pack in the crown shop gives a great experience boost for your pet, so try that as well. It takes many games in order to level up your pet, but eventually, it is worth it. And as you get your pet further, gaining experience wont seem as difficult.
And the best game to play is the Maze Game, it is fast and is the easiest out of all of them.
Do you mean pet power to play games? if thats the case then I think KI should lower pet cost to play minigames. just so we can advance our pets in rank a little more comfortable with out emptying our wallets constantly to buy pet power. For pets sake W101 is already pay to play. don't you think KI is already making enough money on subscribers? Now they want more money with Crowns as well. What the Heck! Give us a break.