Nice art! You have that angle covered. Now about your question, do you mean game design specifically, or game development in general? For the former, try looking more carefully at the games you like. Try to figure out what makes them tick. Try to design your own, see what works and what doesn't. Read what other game designers wrote about their experiences with it. But most importantly, practice.
If on the other hand you mean, game development, that's a bigger question. It all depends on how much you're willing to learn -- how much programming, in particular. You can make games in many, many different ways, so you'll have to narrow it down some. What genres do you like?