Ever heard of Udemy?
It is basically a site where instructors make classes. I have a class that teaches 60 games in C2.
I just started to take it 3 weeks ago when I bought the license. It is literally night and day from 3 weeks ago from what I have learned. Mostly from making actual games per his lessons.
Also from adding to those games and making my own versions of them. Simple games, but using a lot of random behaviors. Which is great experience. Plus anything I haven't learned yet a simple google search or forum search will explain everything!
It isn't free of course, but nothing is. I went out and put this $129 on the credit card within 2 days of buying his class. I knew this engine was legit and was completely and totally worth a mere $129.
Just make a clone of a game from scratch or as much as you can and you will learn loads of things.