This is helping me at the moment: 5 - 10 mins a cycle - longer the better.
1. Choose a small object that means something to you - pebble, crystal, ring - anything.
2. Choose a place you feel warm and safe ie. an area of your garden, bedroom etc..
3. Hold your object in your hands and close your eyes and relax.
4. Concentrate on slow deep breathing (as deep as you can go)
5. Concentrate on how relaxed your body is feeling, remember this feeling.
6. Next time you get a craving - deep breathing and remember feeling relaxed and/or repeat whole exercise frequently.