It won't help if you suddenly change the way you dress or act; people (especially people your age) can smell a phony and won't react well to your obvious and sudden effort to be cool. What you can do is enhance that existing you, and ensure that it displays an aura of fairness, eloquence, transparency, and council-material. Do some informal polling (get friends to help if you can) to find out if people want a new vending machine by the gym, a different lunch item in the cafeteria, another dance added to the calendar, etc. A clever campaign won't do much for you if you have nothing to bring to the table.

Summary:
Be consistent about who you are throughout the campaign. Find out what people actually want.