There is no method that works unless you are absolutely certain that you want to quit! The first step, then, is to be absolutely convinced that you don't want to continue smoking. And this is achieved by having a good motive A REASON.
Not everyone gives up smoking for the same reason. Find yours.
For some people, for example, the health of their children is more important than their own health. Other people have given different reasons, like:
Think about it what are your reasons? Make a list. Put them in order of importance. Once you know your reasons, repeat them again and again every day, at every opportunity when you get up in the morning, during a break at work, before going to bed and think deeply about its importance.