Make sure your info on your resume is correct. If you lied, then make sure you can back it up with more lies. You might think this is fucked up, but I have interviewed lots of people who could not answer basic questions about skills they had listed on their resumes.
Try to relax. They know you are nervous, but you don’t have to sweat buckets.
Make sure you eat, or carry some candy in your pocket. Long interviews are not fun if your blood sugar is low.
Wear a suit unless other wise told not to. Also, don’t just go for black and white. Make sure you have some bright color. A power red tie or kerchief will be remembered.
In the question faze, don’t bullshit. If you don’t know the answer, say so, and then ask if they mind if you theorize. It shows honesty and creativity.
Be ready to answer lame ass behavioral questions such as “tell me a time when you had to use your leadership skills.” Sadly, answers to behavioral questions will get you hired more than skill based answers. Companies can always train people in job skills, but finding someone with interpersonal skills is a real plus because they can’t be learned quickly.
Also, if they give you a question that does not have an answer such as “Your deadline is a week away, and you have three weeks of work to do. How do you handle the situation?” That is a loaded question, and tell them that it is a hypothetical question, and that you cannot have an answer until you are put into that situation, but you will give it your best.
If asked something funny like: “Why are manhole covers round?” Don’t sit there with a dumb look on your face. It is a type of question to measure creativity and reasoning skill. Answer it the best you can, and try to be creative. (BTW, they are round so they won’t fall into the manhole)
As for asking about money, I would say, don’t do it. IMO It shows lack of tact. After all, you can always bargain after the job offer is made.
If you get hammered by asses who like making people sweat in interviews, turn the tide by asking them what they do in a common day of work. It is amazing how that will throw a wrench into their machines. You will also be amazed when all they come up with is “drinking coffee” 
Be polite. Always thank them for taking time to do your interview and thank them again before it ends. Also, don’t offer to shake hands unless it is offered by them first. Trust me on this one. People at work don’t shake hands on a regular basis, and having a hand trust out to them might throw them into a kilter. Also if set in a meeting room alone, stand up when the interviewer comes in.
If you have to use the bathroom, then ask before the interview begins or just at the end (better at the end). If offered, say yes and go, even if you don’t have to, it will allow you to collect your thoughts.
If taken out to lunch, eat something light and make sure it is not messy. Also, don’t order anything alcoholic, even if they do.
Don’t be afraid to joke with the interviewer. Small talk will make the day go a lot easier, but try to stay on topic. No tangents and don’t brooch subjects. Asking them how they are or how their day is going will go a long way.
After the interview, make sure that you ask how long until a return call, if any, will be given to you. Also ask them if they will contact you either way. That way, you are not left hoping. Being turned down is better than no word at all.
Oh yeah, make sure you bring your portfolio with you and a copy of your resume and cover letter will be nice too. You might be surprised with how many people forget the basics.
Have fun, and good luck. BTW, interviews never get easier. You will always be a wreck.