Despite the advertising, with me they take away sensation and it will take for friggin' ever to actually orgasm.  Okay, not really, but it was easily double my normal time.  Your results may vary.  But for me they damn near knocked out all sensation - with eyes closed I couldn't have told you if anything was touching my prick.  At the end we were both wrung out just trying to reach my finish line, and it started to feel like work.

I won't EVER touch those again!

Jerk off before you meet them. Seriously. Get the easy one out first. Common practice.

They don't pick those guys for their looks.

First things first is to get comfortable with your partner.  
Diaphragmatic breathing. Concentrate on your stomach moving up and down.
Stop thinking about your orgasm.
Be in the moment, feel the pleasure and pay attention to it from a bodily holistic perspective, not just your unit. Don't think of baseball, I certainly do not want to think about Sammy Sosa while coming, and it will make you go faster.
Be relaxed, but do not relax. In other words, don't just lay there expecting something to happen, but try to relax and be excited about things.  

If you ever injure yourself and need a legitimate prescription for pain killers from a doctor, make it Tramadol. Seriously, that is HUGE for premature ejaculation. It is not only a pain killer, but also increases serotonin levels, which have been shown to dramatically delay ejaculation. Two a couple hours before hand.

Finally, send MrJaxx a check for $200- for curing you. Go forth and bang my son.