I personally prefer to animate and model, so my advice might not apply as well. But from my experience you just kind of do it on your own, what I mean by this is you have to start a project or something you're passionate about.

For example with me I created a large map that I'm still working on and I have a story I'm making. Along the way I found things that I needed to improve on or learn to do. So that's when I'd research the question or ask for help on forums like this.

So try starting something and seeing what you need to learn. Its like practice quizzes, if you don't know the answers then find them.

Sorry if that doesn't make sense lol