Have you heard of an app called Seat Guru?
This website specializes in helping you find the best airline seats. Imagine that, an entire site dedicated to helping you find the most comfortable seat on an airplane.
If you want to use this for getting the best seat on a particular flight, just keep this site open in a separate window when booking an award. This way, you can see what are the highest ranked seats on your particular airplane. Then you can use that to your advantage before actually choosing your seat online.
How awesome is that?
I use it especially when booking business class flights because I only want airplanes that have lie-down beds. Not all business class is equal! Some actually suck.
Visit the site at SeatGuru.com