I would suggest the book "The Willpower Instinct" by Kelly Mcgonigal: http://www.amzn.com/dp/1583334386.

You can also look a great talk she did at Google: http://www.youtube.com/watch?v=V5BXuZL1HAg

In brief: sleep, exercice, healthy food and meditation will boost your willpower.

Edit: fixed Youtube link.