Think about your reasons for quitting as this leads to motivation then be determined. My doctor told me motivation is all that is needed to quit, i agree if the reason is big enough (throat cancer ect..) yes for sure that would motivate just about everyone. My reason was imagining i was on my death bed at a young age knowing it was my fault i have shortened my life and now its over. This was a strong motivation that is still with me but i was still struggling to quit. Whilst i kept trying again and again my determination increased, by this i mean my many decisions to quit became a lot firmer with each quit attempt. Having a reasonable motivation combined with a developing determination led to having a reason, making a firm decision and most importantly not changing that decision. This was the backbone of my success. How i dealt with withdrawals and cravings is in my other posts. Each attempt gives you something that can be used in the next attempt, the ads on tv which state "never give up on giving up" can only lead to success, don't be discouraged. Discover your motivation and let your determination grow until you succeed.