I find it easier to turn negative self talk into something neutral first, like "I'm gross for not exercising enough!" …..change to "I didn't walk today but maybe I can try 20 min in the gym tomorrow." That is easier for me than "I love my body and it's ok if I missed working out today!!! Yippee."

I listen to meditation mp3's and one is supposed to be for the morning before starting the day and they have an unusual take on this. When you start thinking negative thoughts like "Ugh, I don't want to go to work today." …keep the negative tone but plug in positive sayings…like "Ugh, it sucks that I'm going to be so productive and successful at work today." It is kind of dorky but it sort of works.