Some things to keep in mind...

Here are some tips I've found to help make you more credible.

Make sure you use your contact info, whether it is at the end of an email,on business cards, or whatever.
Make sure you are up-to-date and fresh on your information.
Use your supervisor's name and department when meeting with faculty and staff.
Be involved! The more involved you are, the better you will be off in the long run.
Be quick to respond to emails, phone calls, etc.