Start exercising with deep breathing. It will protect your health and lungs. Then check what makes you restless and you want to smoke. Practice of meditation, though somewhat difficult but can help here. Staying away from smokers will be also helpful.
Breaking habits is not easy; that's where pharma companies make money. But once you resolve, fighting to get rid of the bad habit will also help you learn more about yourself and other shortcomings.
You can help the HubPages community highlight top quality content by ranking this answer up or down.