A support forum like this one. It really gave me a sense of accountability in my quit and wound up making quitting a much more enjoyable experience (something I didn't think possible).
I also read Allen Carr's The Easy Way to Quit Smoking. Some people don't like that book but it really helped me realize that smoking did nothing positive for you at all and that quitting is one of the best things you can do. I still wouldn't call it an "easy way" but that book helped me and many others.
I smoked for 20 years. The first 10 years, it was a very sociable experience. The longer I smoked, though, the more of my smoking friends either quit or I lost track of. I eventually grew to think of smoking as living under a dark cloud (literally and figuratively) of negativity, isolation and poison. I wanted out of that. When quitting, I really tried to focus on the positive.
In time, you will see that smoking does absolutely nothing positive for you whatsoever. There is no negative in quitting. It can be tough but it is worth it.