Who here has the Twilight Saga: The Official Illustrated Guide? If you do, don't wait up on Stephenie doing Midnight Sun or any prequels/sequels!
Look through the backstories of every single vampire/werewolf/human in it. Do stuff on the Irish Coven, Anne and Victoria's coven, the Olympic Coven and the Volturi; create their stories yourself! It's a great way to write -- if you're stuck for any ideas, go with something you love! I wouldn't go with writing Midnight Sun though; Meyer promised she'd write it, it got leaked and she refused. So don't bother. Just do the ones that weren't mentioned in the saga. That'd be cool.
Maybe even mix the characters with a few from other books you'd like...? Way cooler!