Before you leave the job fair, return to the booth of any employer in which you have an interest. Wait for a break in the action, then step up to the Recruiter and thank them again for their time. Let them know that you will be in touch and that you look forward to speaking with them again.
Most recruiters dread having to go to a job fair. Do your best to make life easier for them.
This lasting impression will help the recruiter to remember your name and face when you do make contact again. After all, there will be a stack of one hundred to two hundred resumes for the Recruiter to filter through after the job fair is over. This is a guarantee that you will be remembered.