6. Bright eyes.
You want to see nice clear eyes with a smooth clean surface on the cornea/eyeball. Check to make sure the fur around the eye is nice and dry, with no weepy stuff or gunk. (Did you know that weepy eyes can be caused by dental issues?)
7. That gorgeous fluff, and the skin underneath it.
Rabbits are big self-groomers, and if you have a bonded pair, they will also groom each other. With all this futzing with their fur, a nice full soft coat is typical. Any dryness, oilyness, fur that is sitting oddly along the body, bald patches, or other disruptions in the loveliness are something to notice and watch closely. You may find a little evidence of some poo stuck under that adorable tail...go ahead and clean that up and make sure that nether region is nice and dry. Some rabbits have very dense fur, so do feel and look around to find any lumps, sores, scrapes, or other injuries. Check the skin for any redness, urine scald, or sore hock. And of course, get to work on any matting that has occurred asap and you'll save both you and your bun a lot of aggravation.