Preregister: It may seem like a small step, but this gives you a chance to review the companies in attendance and make other possible preparations to further align your presentation with the needs of a specific company. Also, at a popular career fair, there may be attendance limits or long lines at the registration table, which could cost you valuable time at the fair.
Research the companies: After learning what companies will attend, research who they are and what they do. This allows you to approach your first interactions with the hiring team confidently armed with knowledge about the company.
Make a plan: If you receive a map of the career fair with your registration, take a moment to prioritize your time; this will ensure you contact those companies that interest you the most. Quality is more important than quantity when you are trying to attract a Recruiter's attention.
Resume: Whether you use professional resume services or you prepare your own, it is very important that you have many (20+) copies of your resume. Plan for 1 copy for each company in which you know you have interest as well as a few extra copies.
Letters of recommendation: Bring just as many copies of your top 2-4 letters of recommendation to provide to those Recruiters who show active interest in you. This does two things: It reduces the employer's need to check your references and it often makes the Recruiter file your information differently from the other resumes they have received. If you don't have letters of recommendation, bring your reference list.
Introductory Letter: You don't need a cover letter at a job fair because you are there to introduce yourself in person; however, having a letter to send with the Recruiter for the hiring manager can be a nice touch as this may be your first introduction to another contact with the company.
A Briefcase or Folio: Not only are you bringing a large amount of paperwork with you to the fair, you will be picking up a substantial amount of information while you are there. A briefcase or folio is both more convenient and more professional than a backpack or plastic bag.
A career fair is basically a series of informal (sometimes formal) interviews where you have the chance to make a strong first impression and expand your professional network. It is critical that you dress appropriately to make a positive impact.
Dress how you would for an interview. For most professional positions, this means a suit and tie for men and a professional blouse, jacket, and skirt or slacks for women. Don't overdo it though: You should still look the part. For hands-on or "blue collar" professionals, khakis and a button down shirt may be more appropriate than a suit.