You need to get a piece of paper or turn on your computer and create a word document.
Print out from the computer the job description so you can create some questions to ask on your interview.
Also print out a copy of your resume, the addresses/contact info of where you have worked and your references that you will take with you to help you fill out the job application.
Get a map and find out where on the map(s) where the job interview is and if you have time go out and drive to where the location is so that you can figure out the distance and time it takes to get to the interview. You can either use a regular map or some other mapping software like www.mapquest.com.
Get the clothes and accessories you will need to wear to the interview the night before and also figure out how you want to do your hair.
On the day of the interview you want to get ready at least 2 hours ahead so that you are not rushed. Put all that you need for the interview in the car like your resume/maps etc.) Also make sure that you have enough gas in your car and if you are taking public transportation add extra time since it takes longer to get to the interview when you take this method of transportation. Yes it saves you gas, but it also takes a longer of time to get to/from the interview and is usually hard on your feet.
Get there early, about 1/2 hour to fill out a job application if told you will be doing so.