I was smoking 40 to 50 cigarettes a day and had tried literally everything to stop but never could (over a 25 year period). I've now been stopped for over 3 months, although I use a vape tank (very low power one) that I'm planning on quitting using soon.
The way I finally succeeded was to realise 2 things:
1) The actual nicotine withdrawal isn't that bad, it's the fear of not being able to cope with it that gets you.
2) In the past I've thought "I'm going to use patches INSTEAD of smoking. Or gum INSTEAD of smoking. Or vape INSTEAD of smoking, etc".
If you think like that you can't help but compare your new thing to smoking, and it doesn't compare, so you end up going back to smoking.
What I did instead was think "I'm going to to quit smoking for good. And I'm going to use patches to get over the nicotine withdrawl (so NOT instead of smoking)".
I used patches and an ecig when I felt really nicotine withdrawn - like a couple of puffs of the vape thing to just get over the bump.
After about 1 week I stopped the patches, and have used the vape since, but kept stepping the nicotine content down.
I now don't even think about cigarettes, although at 7 days, 10 days and probably 20 days I was dreaming about smoking and it was SOoooooo good in my dream. I even dreamed I was smoking cigars and a pipe (I've never used those), probably because of all the smoke they produce lol.