Be yourself as much as possible (**I always add this little disclaimer: within reason). Also, just try to make friends and ****. I don't know about your school, but at mine, the president is pretty much a figurehead, so a lot of the candidates are just people who acted unique and cool.
During the speeches, make your speech as un-speechlike as possible.
Make it a rap, or a poem, or a song. Showcase one of your talents. You probably already know this, but when it comes to teenagers,
EVERY contest is a popularity contest.
It's not about the race at all, just make people like you lol.
Hope this helps
Also, cookies.