Here's what you'll need:
1) Manila folders (one for each interview)
2) A stack of index cards
3) A pen
4) Paperclips
5) Information pertaining to your interviews, including the name of the firm, time, date, interviewer's name(s), the room number/location of the interview, and what information they need from you (resume, etc.)
6) A stack of neatly stapled resumes, transcripts, and writing samples
Take one manila folder and one index card.

Write the name of the firm on the unlined side of the index card, as well as the time, date, and location of you interview.

On the lined side, write your interviewer's name(s) and where they graduated from. List any connections you might have. List what your interviewer's interests or recent accomplishments are. At the end, it might help to write up some talking points if things get slow, or some good questions to ask that you can't find the answers to on the firm's website/NALP/etc. Don't be the guy who asks questions like, "Does your firm specialize in IP Litigation?"

Now, paper clip that index card to the top front of your manila folder, unlined side up. (Bobby pin is used here because I'm out of paperclips).

Now, inside that folder you're going to put all the information the firm has requested of you - your resume, your transcripts, your writing sample.

When you've done this for every firm, you should have a stack of manila folders with index cards face up.
So now, when you go to your interviews, you are fully prepared. Not only do you have all your papers prepared and targeted to each firm ahead of time, but you also have index cards that before each interview, you can sit down and review. No more wondering if you read that thing about some other lawyer at another firm, or forgetting that you had a connection with an interviewer or the market they're in. No more looking at your terrible handwriting on the back of the OCI schedule your law school gave you (if your handwriting is awful, you can use printer paper for this project as well, though I find the index cards to be sturdier).
Make sure that before the interview, you take the papers out of the folder and toss the folder out. The index card can be saved in your pocket if you feel like you will need the info later, but I would recommend throwing out the whole thing and making sure you saved the information that was on the index card on your laptop.
Best of luck, future lawyers!