Take a minimum of forty minutes for yourself everyday

The first thirty minutes should be to exercise and the last ten minutes to shower!

It's probably better not to do this right before you sleep because you won't be able to fall asleep so easily. Do this maybe before you start your homework (get the blood pumping).

I always stretched while doing homework. Staying flexible (or increasing flexibility) means that your muscles won't creak as much as you age. Scary words, but 'tis true.