Have an assload of questions about your role. Bring a pad and pen w all these as bullets. Almost act as if you are weighing multiple offers your own self, though still being gracious and professionally eager (earnest = bad). Also demonstrate some serious research has occurred, co. origins, SWOT etc. Pick the early as fuck timeslot. Be 5 mins early and piss elsewhere beforehand. Whoever is interviewing you doesn't need to meet you 35 seconds after wiping their ass. And don't be >5 mins early either. 22 mins early is actually bad bus. etiquette.
That's all I got. Wear a tie I guess, depending. If you have a T Soprano Rolex Presidential, leave it at home. Same goes for purple monkstraps etc. Say "thank you for taking the time" after not "so when will I hear from you?"
*I don't think which day matters much or rocking out first middle or last day available. You'll never know if some superstar is already the shoe-in or "will be Friday" or if another round of interviews will occur anyway.