Talk to the admissions department of the college you attend. An adviser will be able to tell you where the roommate bulletin board is located, if there is one, or where you can post an ad for a roommate.
Create a flier or business card to hang on the college roommate board. The information should include your name, phone number and basic information about the housing. Basic information can include the location of the rental, but not the address, the monthly rent and cost of utilities.
Send an email to your contact list informing them you are looking for a student roommate. Word of mouth and personal referrals may help you locate a trustworthy roommate.
Post an ad on college roommate websites. If your college has a website that is available only to staff and students, check the site for a student forum. The forum may have a Web page dedicated to student housing and roommates.