Congratulations, man.

One thing you might want to try (make sure you can remember to do it) is looking at your hands. What this does for me is make the dream much more solid. You can stop and take this time to gather yourself, and realize that this is your dream, and you can do whatever you want. Visually, the dream will probably become much more detailed, around you, and - if you have any doubt in your mind about being omnipotent - the physics could be tough to control, and it could feel like waking life.
Just take the time to relax, and remove the doubt from your mind, that you can do anything. Then, (relating to the situation you were in, being locked in school) just run (or fly) in any direction, phase through the walls and end up outside.