I have the credentials.
The hard part is not quitting, but avoiding starting again. After quitting, the desire to smoke can last for months or years. I used to dream about smoking. I would even looking forward to bedtime so that I could “dream-smoke”. 🙂
Some things I found helpful:
1.Remove, or pack away, everything that reminds you of smoking: ashtrays, matches, etc. Of course you may still need matches to light Shabbos candles, but at least keep the matches out of reach the rest of the time. I kept some cigarettes on hand so that I wouldn’t panic, but I packed them away so that they were out of sight and it would take several minutes to access them.
2. Try to avoid going to places where other people may be smoking.
3. Do regular cardiovascular exercise. It needs to be of sufficient intensity that you have to breathe very deeply. With each breath, you’re reminded that you wouldn’t be able to do that if you smoked.