Job hunting is always so much fun, here are some tips that I always follow.
This is probably the most important. People can usually tell if you're fake or phony, and since you'll be working with them everyday, why act like that? Obviously though if you're hung over from the night before, it's probably not a good idea to come in and say "dude, I've got this massive hangover!" Basically be yourself, but don't act like a total moronic idiot.
They called you in for a reason. They're hoping you can fulfill their job needs, and be someone they want to work with. They are not the enemy, don't treat them as such.
People aren't stupid. If you lie about something on your resume, chances are, that'll be found out at some point. If you lie about something to pass a phone screen, chances are even if you're brought in for an interview someone will notice.
There is not a single person in this world who is perfect. There are people who think they are, but they're really not. It's not a crime to not know how to do something, so don't be scared to say so.
This is my biggest pet peeve. If you have someone in for an interview, keep them updated as to the status of where you are in the interview process, and have the decency to call/email them even if they're out of consideration! There's nothing more nerve wracking for an interview candidate than to not have closure. An email thanking them for their time, but they're not what you're looking for takes all of 10 seconds to write.