My parent's smoked for years, though they quit when my mom was pregnant with me. I never once had the urge to even hold a cigarette in my hands, and never started. Most everyone else in my family smokes though: Aunts, uncles, cousins, they all smoke. I see how tied they are to their cigarettes though. They'll regularly excuse themselves from a dinner, movie, family event, party, etc, etc, to satiate their craving. They all have awful bouts of coughing fits, their cars smell, they don't always look terribly healthy, and I can't imagine how much they spend on them with a pack being nearly $10 these days in NJ.
However, I do completely understand how their addiction works, as I too, was addicted to sugar. It was so bad, that I would sometimes go to the store, grab a pack of little debbie snack cakes, and eat almost the entire box in a single sitting. I would eat mountains of pasta, fast food, and hoagies constantly. I took a hard look at myself in the mirror one day, and I hated myself. I was 27, and I had high blood pressure! So, I went cold turkey. No more white bread, rice, pasta, foods with ANY amount of added sugar, nothing with carbonation, started at the gym, and I've lost 15 pounds in a month. I already feel stronger, I sleep more soundly, I have more energy throughout the day, and I plan on training for the MS Bike to Shore to keep me motivated and my goals on track.
Everyone handles addiction differently. For some, weaning off a habit is easy, for others, it might be one of the most difficult tasks they attempt. But if you set little daily goals for yourself, and accept occasional mishaps as being inevitable (and not at all detrimental to the bigger picture), then I think that's a great place to start.