A recent read called The Art of Extreme Self Care by Cheryl Richardson has been helpful here, particularly the idea of a To Don't list (the opposite of a to-do list).
Here are some of mine. I no longer ....
1. keep things I never use or even look at, not even if I think they might "come in" some day.
2. feel guilty about picking up new hobbies/interests and dropping old ones.
3. remain on emailing lists which don't benefit me in some way, especially if the emails make me feel dissatisfied or that I should buy something.
4. eat when I'm not hungry.
5. waste my precious me-time on twitter and facebook.
6. feel guilty about not being perfectly organised and buying a few items at a convenience store rather than traipsing to the supermarket to save money.
7. drink more than two gin and tonics.
What might be on your To Don't list that would help you live more simply and look after yourself better?