At work we have started a Biggest Loser game. Every Friday we give $2.00 and get weighed. After 16 weeks the person who has lost the most percentage wins the pot! Pretty good incentive!
One of the most influential books I've ever read is Conversations With God by Neale Donald Walsch. It teaches us that our thoughts are very powerful, and actually determine the course of our life.
One of my resolutions is always to be aware of what I'm thinking and saying, and if necessary, change those thoughts and words to ones that are more loving. This is much more difficult than it sounds!