First, get comfortable with the engine.
Then, you need to learn GDscript or python. I say python because GDscript is very similar to python and you feel more familiar with GDscript. This step is not necessary.
I recommend Hartbeast's rpg tutorial and the 'How to make a 2D game in Godot' by GDquest for learning GDscript and some to show you how one would make a full game.
After that, you will need to decide what kind of art style you might want to use for your games. I recommend pixel art or vector art. And learn some basic techniques, shading and all of that jazz.
You will also need to know how to make sound effects and music for your games. There's tons of tutorials on YouTube on which programs to use, how to use them etc.
Along the way you should pick up some game design. You can watch GMTK videos. And you can search up on YouTube 'game design tutorial' or something like that.
Something else you should do along the way is making finished projects. Even though they're really small, Its a good way to stay motivated and practice what you recently just learned.
I probably missed something but I think I covered the main points.