BUILD SOMETHING.
Learning concepts without the ability to apply them are essentially useless.
Get your hands dirty and build something that would be valuable to you and solve a problem for yourself.
Don't get hung up on doing it "right". Focus on making it work. Don't worry about how it'll work for a million users. Right now your focus is on making it work for one user.
As you go you'll hit walls. Research how to get past them and keep going. Again, you're going to make mistakes. DO NOT GET HUNG UP ON THIS.
Making mistakes is part of the journey. Even the best software engineers in the world rarely get things right their first try. It's part of the process.