My friend and I used to smoke a lot together, especially back in college. I was able to give it up when I left the university, although I'll still have a smoke from time to time, usually when we see each other in social situations. I think it helped that I was really just a social smoker, and as I got older, I started becoming aware of how bad it makes me feel after. She, on the other hand, has kept the habit, especially since she has a stressful job. But she promised to quit when she turns 30 - which will be in September. How do I help her get through it?