I've been rather impressed with Anton Krupicka's running style. Yeah, he's one of the best trail runners in the world, but his basics are worth paying attention to.
Go on YouTube and look up videos of him. Minimally-padded shoes. Very short strides, rapid pace, low impact, no foot slapping. The documentary "Unbreakable: The Western States" also has a lot of valuable footage as he starts fresh and after exhaustion sets in towards the latter parts of the race.
http://www.ws100film.com/