The smoke brings you no good but health loss. That is the first fundmental thing you need to keep it in mind before taking other counter measures.
The second, help yourself develope good new habits that maybe alternatively taken to avoid thinking back smoking, such as, body exercises, music if you didn't like before.
3. Ease your mind at usual time and find other suitable way to depressurize. Most surveys tell that smokers first did smoke due to the need to depressurize themselves from problem of life and work.
4. For smoker who smoked for quite long time, better go and find medical aids from expertise doctors. They have experience and list of knowhow to cope with it.
5.if there is the fifth or more, they should be coming out from doctors.
After all, no matter initiatively or passively,keep yourselves far away from smoke, make your life green and valued.