Edging is probably one of the greatest tools for overcoming premature ejaculation, but it can't make you better in bed alone, for that sex is needed. There are simply to many sensations in sex that one cannot reproduce during edging. However, edging will help you in adapting faster and getting to know your sexual response better during high arousal situations.
If you can experience a very high arousal state for longer periods of time during edging your body can start adapting to it. There are many ways you can do this, one of the preferred for me is edging near PONR for a minimum of 20 minutes. What you need to do is edge till you reach near PONR (point of no return, is the point after which the ejaculation starts ) and try to stay erect and near PONR for about 20 minutes. It doesn't matter how you do it as much as it matters to reach that 20 minute mark. In other words just make sure you are erect and near PONR but do not stroke to much.
At first this will be very hard, but as you repeat this edging session you will find that you will have more and more control, and that is very important. Over time what was a struggle to not ejaculate during a period of time, will turn into high arousal edging session.
And this is just once of many ways one can edge. Others who do not have problem with this might want to focus on being more gradual in their approach to PONR so that they avoid creating a habit of rushing to PONR. For most people with premature ejaculation the PONR comes so fast that it doesn't really matter but as you get better the PONR will come later and later so it is a good idea not to create a habit and rush to it.
One on the edging sessions I like to practice is to first very gradually and as with little pause as possible bring myself near PONR (that can take from 5 minutes to 15-20 minutes depending on many factors) then when I am near ponr I will try to back of a few times and find a plateau (plateu edging is yet another form of edging where one tries to stay at consistent arousal level) after a while (10-15 minutes) I will consistently stay near PONR for at least 20 minutes (various things may happen here, for a simple struggle to soft wave orgasms) and after all that I make sure to ejaculate at the peak of my arousal, this is very important since it reinforces the desire to have a full body orgasm rather than just a normal ejaculation.
Then there is the aspect of eding where you start challenging your weak points (this is usually done after a solid progress has been made), so one starts edging with faster pace, different grips, more or less lube, with or without porn (audio and or video).
Granted this is the "ideal" way for me, but it is rarely 100% like that, and that is the point, it is a goal to aspire to.
To add another layer there is a
3day routine which can take all this but instead of ejaculating at the first day, you ejaculate on the third day, this is by far the best way I know to condition yourself to the arousal.
Here is much more abut the aspects of arousal.
All of this acquaints you with your body and rewire and change bad habits for the better, but only with more sex will you get better at sex, proper edging will just help you adapt much faster, it will also raise your confidence and actually show you that you can last long (which when it first happened to me was a very important milestone in my journey).