I'm taking this number by number for you.
1 - Smoking is not only bad for your health, but those around you. Second hand smoke is just as dangerous (if not more so) than first hand. Are you always responsible with disposing your cigarettes? If not, animals could be getting at it, not to mention those poisons would be seeping into the earth, which we are stewards over. You can't recycle those, I'm afraid. Does your God-given life mean so little that you'd trivialize it every few hours by having another cigarette?
2 - You've probably heard it over and over again but figure up how much money you spend on cigarettes. No, you probably already know how much that is, don't you? Now, I want you to think about what that money could do as an offering to the Lord. Given to a charity, your church, what else could that money do than suffocate you? All of your possessions belong to him, why waste them on what can kill you? If you are in financial trouble, why are you still smoking, wasting money like that? Maybe this is really the time you need to quit smoking! God is not only the God of the Vine, but the God of the Worm and the Blistering Sun! (Jonah 4) He isn't shy to send us a wake up call when we need one!
3 - Your family is worried for good reason. It's because they love you and want to keep you around on this earth for a while longer. Do you smoke around them? If you leave them to go smoke, they miss you. If you stay where you are to go smoke... they still miss the nicer smelling you. You do not need to smoke to enjoy the end of a meal, you do not need to smoke to make social occasions more enjoyable.
4 - Properly used, tobacco is a great pesticide... Think on that for a moment. We are supposed to do our best not to offend others to help bring them to the Truth and the Light. How can you witness to those who need it the most with tar breath?
Withdrawal pangs can NOT be worse than dying on a cross.
Most smokers do not wake up in the middle of the night in a cold sweat to have a cigarette. The addiction is mostly in your mind, perpetuated by this world where the nicotine business runs - big cigarette companies, nicorette, nicoderm, scare campaigns (what do smokers do when they get nervous? That's right - smoke!), movies, television, our idol worship... But honestly, it comes down to a decision.
Will I lean on God or my own flawed understanding?
You have something bigger than you to lean on, price has been paid, and all the comfort you need is right there when you ask for it. You can do all things through Christ - you can have the most wonderful life or nothing at all.
Write up a few scripture verses on a cigarette sized scroll and stick them in your pack, or outside of your pack. With all things, go prayerfully forward. Grab more quiet time with Him, read His Word. There is not a single person alive that spends enough time with him. Meditate on him. If you need scripture verses, I'd be more than happy to pull a couple of dozen for you.
Once I did really well though...I set my mind to it and went without for 2 whole months. Then I joined some friends for a drink one night, and I just had a drag, which lead to 2, which lead to "Just 1 cigarette...".
