It's like painting. You don't start with cats and flowers. You start with circles and straight lines. Don't think about how to make the game of your dreams, but

It's like painting. You don't start with cats and flowers. You start with circles and straight lines. Don't think about how to make the game of your dreams, but consider if this is worth spending a half-day-job amount of money for the next 5 years on it. If not you can just stop there. If it is, start with something simple like tic-tac-toe.