I think that the best thing you can possibly have in your arsenal is a supportive partner.
If you have a supportive partner, he or she will do everything you need to quit.
I've asked my significant other if she would be able to talk me through times of stress, and celebrate the small daily achievements with me.
She took the initiative and told me that she will reward me when I reach certain goals.
It's only day six, but I have never felt more confident that I can quit. My partner is to thank for that.