before jumping right into making a game experiment a bit with your new knowledge. Try and make little snippets of common things in games like a simple menu system, using sounds and video and probably the most common - Player movement.

It will save you a bit of time when making your game as you wont have to think about how to do this and that, because you have already tested and made them.

If i go through my game and there is something i dont know, i always make a seperate script and test it there.