Tommy desperately wants to quit smoking. which method has been shown to be the most effective one tommy can use

Tommy would probably want to avoid triggers. People often smoke because they see other people smoking or it is a way for them to get over something. My tip would be to build self-confidence. You won't want to have to want to fir in or try to repair something. Also make a effort to stop. Constantly remind yourself of the dangers of smoking and how much better your life would be if you stopped smoking.