I quit smoking this summer on a Monday while starting a new super stressful job. I did it by not fighting against nicotine fits and instead using all that energy to invest in myself. Someone suggested flavored tooth picks during work hours. They're sold at health food and vitamin stores and easily fulfill the urge to put something in your mouth. Although they don't lower your need for nicotine, they feel like a substitute for smoking. At home, the second I got inside I would do sit ups and push ups every single time a craving came on.
I started to crave the craving. If you're having a really intense nicotine fit, just lay down and describe exactly what the nicotine fit feels like. Describe it in as much detail as you can. You'll start to realize that it doesn't feel like much. It starts to evaporate once you try to pin point the exact feeling. You'll be begging the craving to come back just so that you can describe it. Then, there's no fit anymore. You'll feel fine. You'll feel good every minute you're not smoking.
Just remember, nicotine will raise your heart rate. You'll be looking for something to just calm you down, but cigarettes will only stress you out. Not smoking will calm you down. Keep not smoking.