It’s certainly a familiar feeling, I think what really helps is thinking up projects of your own that rely on the same techniques you’ve covered in tutorials. Applying techniques in your own projects always throws up a few obstacles that, as you figure out (and google) ways of overcoming, really help nail the concept in your mind and give you confidence in your own abilities to apply techniques. So if you just did the Sci-fi helmet course, for example, then maybe try creating a Sci-fi gun using the same techniques or if you just did a lighting tutorial then dig out an old .blend file you have from a previous tutorial and try relighting the scene using your new techniques. The more you think of fun new applications for the techniques you’re learning, the more familiar and confident with those techniques you become (especially if, like me, you have to go back and re-watch the tutorials a few times during the course of your own project :P). Good luck and don’t get demotivated, it’s a feeling we’ve all felt at one time or another! 🙂