Gym, Creative Commons 2.0, photo by combust
Why is so hard to keep New Year resolutions?
It's because you're not keeping it simple. You need to be specific. Instead of saying you want to go on a diet for the New Year.
Make small changes to your daily eating habits, like giving up that daily soda.
If you want to quit smoking, don't quit cold turkey, because that's not going to happen. Instead, gradually cut back.