1) Finish it. I figured I'd start with the craziest idea first, to get it out of the way. You'd be surprised how much more novel-like a finished book is than a thirty-page partial, and it really helps make steps 2 and 3 better in every way.
2) Add zombies, robots, or explosions. Any one of these, or all three, will immediately make your book a thousand times better. "But, Carla," you whine, "I'm writing a touching biography of my grandmother's life during World War II."
Don't give me that crap. You think she wasn't fighting off Nazi robots during her time at the munitions factory?
3) Have a talking cat, dog, rabbit, or inanimate object as a humorous sidekick. "But, Carla--"
It's poetic license, you dimwit. Your grandmother needs someone to talk to while she's slicing and dicing those robots. What are you going to do, have her reflect on life? Snore.
Well, that's it. If you have more advice, I'm sure it's not as good as what I suggest, but feel free to share it anyway.
Have a Merry Christmas!