To utilize what we call the "fun" piano method, you'll need certain things wholly unrelated to piano lessons.
You'll need quarters.
These I use to balance on the back of a child's hand to help them find a proper hand position.
I make a game out of it and allow them to put other things on the back of their hand to see if they can keep it from falling off by keeping their hand in a level plane.
Be careful, for almost all children will raise the shoulder dramatically to compensate for the hand maneuver.
Gently push it down.
The point of the game is not to permanently deliver a perfect hand position, but give kids a feel for what it is like.
Next, you'll need a pair of dice to play the DICE GAME.
In this game you show the child six songs, perhaps using Piano by Number so they can absorb them quickly.
Then, number the songs on a piece of paper and roll the dice.
If the dice comes up number two, the child has to play the song numbered two.
Make the song selections short, say, four bars of Jingle Bells.
This makes it easy to get through, and more turns can be thus taken.
You'd be very surprised how much kids love this game, which is really no more than repetition disguised as a dice game.
Lastly, get a little bell like they have in a library to signal the librarian to come forward.
Use it for a thousand and one games, but mostly to have fun.
Ring the bell when they get a hard part right.
Or have them ring the bell.
Give them one more bell strike for each little task they complete.
Kids like to get as many bells as they can, and will work hard at whatever you want for this silly reward.
Conversely, ring the bell when they make a mistake, to make strictness a little less negative.
You will find that they laugh at their mistakes and are eager to try again.
For children at the piano, jesters are better than pedagogues.