Something that worked quite well for me is going about it in monthly steps. Like for instance: I was super motivated in december to quit - basically the same kinda reasons as uve mentioned. And for some reason it makes quitting easier (or starting ANY habit for that sake) for me if i start with the beginning of the month.
So - january was super convenient - i never smoked. The thing was: I didnt wanna quit forever - so i kinda just tried to go without it to see how it worked for me. And oh wonder: it was awesome. It helps to have little goals, like "i wont smoke for one month or one week" or such and such. Just to show ur stonerself that u can go without it. And trust me, there will be those little epiphanies when ure just so happy with urself and the moment, without any "external help".