When studying, quality is more important than quality. Sure, you can study from 7pm through to 3am, non-stop if you wish; but chances are that you'll get two fifths of fudge-all done. What Zinga does, with his 30 minutes of walk/5 of game, is apparently close to how studying should be done.
Also, good 8-hour periods of sleep at night do wonders. Enough to rest you, not so much you don't want to get out of bed. (Well, that's just me. But 8 hours is what 14+ year olds should be aiming for, or there abouts.)

Also, some find doing something to be the fastest teacher. Like me. No point telling me all about code and such - I'm not going to learn it until I use it several times.

Also, getting a jump on the test is usually good- ask what sections of the curriculum are being assessed. No point studying probability if it's not being assessed.