The first thing to do when you feel cravings coming on is remember the 4Ds -
Delay
Delay acting on the urge to smoke. The urge passes in a few minutes. Don’t give in.
Deep breathing
Take two deep breaths. Breathe in slowly and deeply, then breathe out slowly.
Drink water
Sip the water slowly and hold it in your mouth a little.
Distract
Take your mind off smoking. Focus on the task you’re doing, get up and move around or look at your list of reasons to stop. Anything that shifts your attention away from smoking for a few minutes can be enough for the cravings to disappear.