I'm a practitioner of the strokeless blow job. Many guys just lick your dick, and lay the head inside their mouth, while they basically jerk you off with their hand. That's not a blowjob by my definition - that's a handjob with tongue accompaniment.
Most men enjoy a lot of tight pressure around their dick, as if it were in your ass. What I've taught myself to do is suck very hard, while holding my jaws wide open, resisting the opposing closing force that sucking creates.
And I suck in pulses. Suck, relax, suck, relax, suck... etc. But I don't bob my head up and down on the shaft, most guys won't need that. I keep his dick as far down my mouth as I can handle during the whole BJ. And I suck hard, REALLY hard, but fighting the tendency of the teeth to close down.
The sucking itself draws the shaft further into your mouth. The relax step releases the dick and lets it return a little. This suck-relax cycle creates the stroking sensation that takes a man to orgasm. A third-person observer might think you weren't doing anything at all, since outwardly there's very little visible motion, maybe a small amount of head bobbing.
Depending on his size your tongue should press upward, to increase the squeezing pressure against the shaft. It can also be massaging his dick, although a really thick shaft won't give you much room in your mouth for maneuvering. It's one reason I actually prefer a medium-sized cock for sucking, rather than a horse dick.
Some guys will come very quickly this way, or if they don't your jaws may grow tired, especially when you're first learning this technique. Either way, take a break, and return to more conventional licking up and down his shaft, on his balls, around the head. The area on the crease of the head's corona (edge) is the most sensitive, especially for an uncut guy who still has an intact frenulum there (analogous to the frenulum under your tongue).
When you're ready to make him cum, very gently stroke his inner thighs with both hands, working to his balls with feathery touches. Remember both your hands are free, because all you're using on his dick is your mouth. Some men will give you a warning they're about to ejaculate if you feel the cremaster muscle that surrounds the scrotum begin to tighten, sometimes raising the testicles against the body.
Then you can decide if you want to take his cum in your mouth, or finish him in your hand, maybe taking a facial that might please him. (Watch your eyes, though. Though not proven by research, some doctors postulate that HIV in sperm, along with other pathogens, can enter the body through the eyes, which are more permeable than skin. This is why you'll often see EMTs wearing protective eyeglasses if bodily fluids may be splashed)