Run for smaller roles, like class representative, until you are old enough to run for class president. This will give you some experience and your classmates will see you as a leader. It's also an opportunity to talk with other members of student council who can give you advice on running for president.
Find out what the procedure is for running for president. If you have to be nominated first, talk to your friends and classmates and ask them to nominate you to run. Once you have been nominated, you can begin your campaign.
Come up with a catchy slogan that includes your name. Try to think of some things that rhyme with your name. For example, "Vote for Stan, He's the Man" would be memorable.
Get your friends together and make posters to hang up around the school. Try to stick to a theme with your posters, so your peers instantly recognize these are your posters. Include a large photo of yourself on your posters and your slogan.
Think about what you want to do as president. Do you want to set aside more funds for school dances? Make lunch period longer? These things will be important to your campaign, but do not make promises you can't keep.
Listen to your classmates. Find out what issues matter to them and base your campaign around those things, if they are doable.
Talk to as many people as possible. Be social everywhere you go.
Prepare a speech. Introduce yourself to your classmates and let them know why you would make the best class president. Use humor and showcase your personality.