Hi, Helenearth ---
I definitely agree with everything that's been posted here, there's been lots of good advice offered! But I thought I'd offer my two cents' worth --- this approach always seems to get rave reviews from my b/f.
Basically, the key is to let the tension really build, as others have said. My method of choice for doing that is to approah him really slowly --- you know he's wanting to feel his cock in your mouth, but don't let that happen right away! Tease him a little! Also, don't forget that he has nerve endings all over his body, not just in his cock --- stimulate those other places too. The entire body is a sex organ, in my opinion!
I like to start with some nice deep, passionate kissing, caressing his body all the while, but definitely steering clear of his cock: slide your hand over his torso and stomach, run it over his hips and his butt, and over his thighs, coming close but never quite touching that sensitive area.
Then I'll move down a little, kissing his ears and his neck, and trailing my tongue down his body. I spiral in towards his nipples, teasing them briefly but then giving them a nice firm suckling, then swirl down his belly... Then stop!
Next I move down between his legs, and starting at about knee height, run little wet kisses up the inside of his thighs. Finally, my mouth encounters his balls, which I take very gently into my mouth, rolling them softly around with my tongue.
At this point, I like to tease him a little with my hair --- my hair isn't really all that long, only about shoulder length, but that's long enough for him to enjoy. I move my head in circles above his cock, trailing a strand around him that slides smoothly at first, then catches on itself and ends up twisting around him a few times. I pull my head away gently, letting him feel the gentle tugs and the silkiness of the hair sliding off him.
After a few repetitions of that, I move back to his balls, and then slowly lick in spirals up his cock, trying to maintain constant contact. As I approach the head, I pull away one more time, and blow lightly across the wet skin I find there. Then I lower my head, mouth wide open, so that I'm surrounding his sensitive tip
but not touching it --- now he's feeling my hot, moist breath surrounding him, and he can see my mouth around him, and he tells me this drives him especially wild.
Finally, I close my lips around him solidly, and begin to pump up and down. I have one hand forming a ring around the base of his cock, tight but not too tight, and it pumps up and down in rhythm with my mouth, extending the sensation. Meanwhile, my tongue flicks at his slit every time I lift my head, then caresses the ring around his head every time I descend. He usually puts a hand on my head by this time, guiding me as to the exact rhythm he wants. Every so often, as I can feel him really building, I pull back and repeat the blowing and licking performance, because the change gives him a moment to recover control. Keep going as long as you can, switching back and forth and adding other minor variations, and then you'll feel that familiar tightening in his balls one more time, and
watch out! Get ready to swallow!
Phew, now I think I need to go find my man and give him some of that treatment, it's got me all hot and bothered just describing it!

Sorry this got so long, folks, it looks like I got a little carried away!

Hope this helps, Helenearth!
--- sweetstuff