Also, you might want to go through a standard combat before you actually play. This should let them know how important it is to stay out of combat unless absolutely necessary. 
Actually we did this, it seemed the best way to show the system, and they *loved* the crit system. The last day of our previous campaign I brought characters and ran a combat. I wanted them to see what combat was as well as see the clear differences to the magic system. Coming from epic 3.5 D&D they are all kinda tired of TimeStop/IWin/Etc levels of magic.
