Simple, spend less time jerking off and more time actually fucking some pussy.
Stick it in and go slow, when you feel like you're going to blow, stop and wait until it goes away then start up again. After a few times you'll have figured out how to 'stop' the 'good feelings' at your cock, it's when those feelings get to your brain is when you blow too soon.
Also there's some tricks to not blowing, when you feel you're close, squeeze the base of your cock for a few seconds with your hand, hard but not too hard, that 'cumming' feeling should go away. Another one is to pull down your balls, when a guy is close to blowing his balls 'ascend' higher, so, pull down your balls.
The last one is to just imagine some fat relative of yours completely naked.
