With the best will in the world, Tig, you don't "start" to give up. You either do it with determination or don't bother - no heavy lecture intended, but your mindset is everything, repeat everything.
And, makedamnsure, I endorse all you say. Lung cancer is a foul and horrible way to die. I watched my stepfather die of it, and also a couple of contemporaries of mine. It is not a pretty sight and is a most unpleasant way to go.
I admit that reformed smokers (like me) are in a special league of boringness of their own, but once you've fully realised the unnecessary damage you are doing to your health by smoking you inevitably want to help others to avoid the self-inflicted wounds that the habit involves.