I vaguely remember Allen Carr, but what helped was a small book that i found in a second hand bookstore in Paris, which was called: Comment S'arreter De Fumer En Cinq Jours. A quick search learns that apparently it was written by Dr J. Wayne Mcfarland and Elman J. Folkenberg. It was in french, but that didn't stop me, it was a small book and very helpful.
I was able to stop after trying to stop 7 times in two months. The 7th time worked. If i remember correctly i used breathing exercises and nicotine gum. I also avoided the couch where i would smoke after diner, instead doing something else.
The most important thing that helped was to change how i was thinking. Every attempt failed because i lit up a cigarette and then thinking; i failed, might as well continue smoking. However, the 7th time it dawned on me that smoking 1 cigarette does not mean you failed. You can put it out and just continue to not smoke. It was just the mind tricking me in continuing with my addiction. Thankfully, hardly anyone around me smoked and that was a great help. I stopped 22 years ago and i had been quite a heavy smoker, a packet of cigarettes a day.