Everybody's addiction is different, and it needs to be treated differently. My bugbear is worrying about the security of my supply. I used to go on holidays with twice as much smoking gear as I needed just to be certain I wouldn't run out. I had a complete extra set in the car in case I forgot my main set when I went out. Now I have backups to my backups to my backups to my backups.
Because I knew this was going to be my sticking point, I didn't throw away my tobacco, or even get rid of the ashtray, when I gave up. The tobacco was there if I needed it, so I didn't worry about it. I didn't even start to count the days. It was some time in September, but I don't know the date.
But... it still needs willpower. Lots of people have found that e-cigarettes are a better tool than gum or patches, but all the tools in the world won't do the work for you. You will still get the craving from time to time. If your e-cigarette is doing the right job, then a few puffs on that will make the craving go away, but you need the willpower to not pick up a cigarette instead.
If you do have a cigarette then it is probably counter-productive too worry much about it because most of us smoke more when we're anxious. Analyse why you had that cigarette instead of an e-cig and find a way to avoid the same situation happening again.