Welcome to the site...bit of a newbie here [to the site] myself but you'll find it's a great environment.
Are you participating in the ASX Australian Schools Stockmarket Comp? Was on the runner-up team here in QLD a few years ago (been out of 'jail'/school a few years now), and found it to be a great experience.
Since I'm assuming you're after short-term big gains, check out some of the tips here on the site for resource stocks, as they seem to be the big performers at the moment. The blue chip shares will barely move for you in the assumed 10 weeks or so you may have to work in, so risky shares are the best bet - trade wisely and do some research/read tutorials here on this forum. Just my 0.02, enjoy.
T