There is no "one-size-fits-all" type of technique in achieving being permanently pulled-back. As Jimble aptly mentioned earlier, depends where you fit in on the 'grower/shower' category how easy you may find it. It will range from use of various types of rings (numerous are mentioned in other threads here), various taping methods, and in case of a very tight frenulum, tying to free the foreskin somewhat (again described elsewhere). The bottom line, don't be afraid to try different methods on your own, like the rest of us have here. What works for one may not be effective for another.
To achieve the best permanent retraction you would be best to try to develop deep shaft wrinkles. If possible, in certain cases, it can be just as effective as being circumcized, the foreskin will never, ever cover the glans at any time, it can be that effective.
And yes, the longer the time that you can be back between being covered, the easier you will find the glans drying and adapting to being exposed. I personally don't like the term 'keratinization' here. Some may find there be a change to the glans surface but keratinization implies an extra layer of keratin. The main purpose is to lessen the sensitivity to the glans so you notice the feeling less. This lessening is also in various degrees with different fellows.