Ask HN: How do I make the transition from being a Python beginner?

I've learnt all the basics of Python, the data types, functions, classes and iteration. I've started a project to create Breakout using pygame. I'm done with Learn Python the Hard Way and the other basic tutorials and need to know why you make certain things classes, when to create functions, how should the program be designed, how should it flow and so on. Ideally according to best practices. I feel like I have all the pieces of Python but don't know how to start putting them together to make something that works. Any advice?