In addition to the fastpassing for the big rides, etc. you can spend at least an hour or more in the Animation Building. Go through the tour, take a drawing class and meet the characters. If you're lucky, more bonus characters will randomly show up too, but at the very least you'll get Sorcerer Mickey with a DHS backdrop, a "current movie" character or group, the Incredibles and I think one more are always there. You may find you really enjoyed that drawing class and want to do it again.
If you have photopass, keep an eye out for the photographers in different spots and really get your money's worth.
Indiana Jones, American Idol and Lights,Motor,Action take a while and definitely will fill up time. Check the times guide and work it into your plan as best you can.
Star Tours has so many variations that you can ride it 5 or 6 times and hopefully see a lot of different versions. You may even be a rebel spy!!