The biggest way to speed up becoming incontinent is already having some issues or a naturally weak bladder. My bladder is genetically defective and is so weak that I need at least guard pads in my panties, if not diapers. If I tried a program of 24/7 wearing, I'd be beyond the point of no return in four months flat. I think this is what makes it faster for some than others; the idea that no two bladders are the same, and each body responds differently to new diet and permanent diapering.
If you happened to have a very healthy bladder and still wanted to go through, try going for a time without a diaper on but still letting go and wetting yourself, convincing yourself through hypnotism or conditioning that it cannot be helped. Maybe it is just how I responded to it, but having that happen to me made diapers seem like a very good solution, and I gladly relinquish control when in one. What people say is right -the hard part is the mind, and the body is just time. I'd recommend taking up meditation or a martial art to develop a stronger control over your mind for this purpose.