Struggling to Retain Java Concepts — Any Tips?

I've started learning Java because I've heard it's a great way to dive into programming. I'm currently about 80% through Codecademy's Java Course, and I really enjoy it! However, I've noticed I'm forgetting a lot of what I learned in previous lessons. I think I made a mistake by not practicing in a Java file right after each lesson. Now, as I work on a project, I find it tough to recall what I've learned. Does anyone have advice on how to better remember my lessons and make progress in Java without constantly having to look things up? Should I try another course or maybe watch supplementary videos after I finish this course? I'm feeling a bit lost here.