There are many things to suggest, I just don't know where to start...
1. Search this site for examples of portraits. "lightingman" is a great search word.
2. Don't plan on sleeping, plan on learning, or else you've wasted your rental money.
3. Do you have a way to fire the lights? I'm unfamiliar with 750 travelites, but you might need more equipment. 30D+50L+420ex won't make strobes work.
4. Practice a lot on something before you get to the real people. Practice a lot. Find a picture that you like, and practice on something, like a doll, until you can replicate the picture.
Jeez, there's so much more... but I'm at a loss.
MKIII, 40D, XTI, 70-200 f/4L, 100-400L, 17-85 IS, 85 1.8, 100 2.8 Macro, 580 EX II, 550 EX, Bee's, PW's