First, use Nintendo’s WarioWare: D.I.Y. to create art, rules, and music for your game.
Then play the game.
Britton Peele reviews the design process:
Start by drawing the art that will go into your game. This was by far the trickiest part for me because I’m a terrible graphic artist in every conceivable way. However, the game’s tools are easy to use, and you can also use assets from other sources, including pre-made games and a variety of stamps …. You end up creating the background and all objects that the game uses. This includes drawing separate frames for any animation you might require.
… Next, you’ll probably want to design how the game is actually played, which can be complex, yet easy to understand. Everything operates on if-then statements. For instance, you can tell the game, “If the balloon object is tapped, display the balloon popping animation.” Then, “If all balloons are popped, the player wins the game.”
You’ll probably also want to fill you game with music and sound effects ….
– Britton Peele @ The Daily Toreador
I haven’t played with WarioWare D.I.Y., but it looks like a nice little system for bringing game design — including the principles of structured programming — to the masses.