Deciding to stop smoking is the easiest step....stopping and remaining stopped is the hard part. Some studies have shown that support groups for smoking cessation have been helpful for many (most local hospitals offer these groups free of charge). I would also suggest talking to your physician in case a medication may be needed to help cut the urge to smoke. Also, if you are thinking of taking a quite smoking aid (the one's available at the local drug stores), check with your doctor first before taking them.
Whether you go to support group, individual counseling and or medication, the choice is entirely up to you. Takes some time to alter the brain, thinking and behavior. First figure out why and when you smoke: times of stress, talking on phone, while on computer. Then look for what else could you do besides 'light up'; such as take a walk, light exercise, yoga, or perhaps a piece of sugar free candy.
Also, let EVERYONE know you are taking the steps to stop smoking. The more emotional positive supports you have, the better your outcomes will be. Remember, this will not happen over night, but at least now you will control the smoking and not have the smoking control you.