Don't be afraid to just play with Blender. If you ever find yourself wondering “What does this button do?” just press it and find out. Now, if you're working on something important, you should probably save first, but definitely make it a point to experiment and try things out. By this kind of playing, not only can you figure out how to use new parts of Blender, but you can also find new ways of using existing features in cool ways that might not have been intended.
Working in 3D can be incredibly serious fun, but it can also be addictive. But too much computer time can ultimately hurt the quality of your work. try to step away from the computer for a bit to rest your eyes, get some food, stretch your legs, or even talk to another human being.