I've been a smoker on and off for 20 years I've quit and come back I usually smoke 4 or 5 sticks a day. I really want to quit for good how do I go about it?

Get a plan. Good site to start with. It helps you set goals , sends you texts to help and offers activities to replace smoking habit. Start here. http://www.cdc.gov/tobacco/campaign/tips/quit-smoking/