Just make games in Unity.
I started off making my first game off one of Brackeys tutorials, with no knowledge in C#. I then polished the game, adding more elements to it and features. At last, I uploaded it to Newgrounds, which made a total of 800 views.
I received a lot of reviews as well, with idea’s improvements, and what not. Which lead me to another game. This is my 3rd game, and I already made 80% of it out of pure memory and understanding, no tutorials or anything.
Basically just challenging myself, and searching Unity manuals and google for answers. Every time you use it you grow in it. That’s at least what I did.
Hope that wasn’t too weird. I’m still not an expert, but I’m teaching myself this way.