How do you quit smoking without using the patch or gum?

I’m thinking about quitting smoking. I know I want to quit within the next 2 years. The only thing is that I really enjoy smoking. I smoke roughly 15 a day. I would like to know how to quit without using the patch or gum. I can’t quit all at once but would like to ease into it by smoking less and less. So what I really need to know also is…

How do you make yourself smoke less?