I have been giving blow jobs to the same man for 10 years, and although he has enjoyed them all, from my first, wet lame attempt to the most recent my technique has improved greatly with practice, and it is at his request I share this.
I don't think position matters a great deal for either party, providing you are both comfortable. He needs to be able to relax and enjoy himself, you need to be relaxed enough to focus on his cock. I normally find kneeling between his legs while he sits on a comfortable chair, or kneeling on the bed between his outstretched legs as he lays back work best for us, but experiment with different positions till you find one that suits. You might find that him standing, you kneeling at his feet exciting, something kind of slutty about kneeling at a guys feet and sucking his cock while he stands above you; be careful though as he has to not quite let go, not totally relax, or he will fall, probably taking a fist full of hair with him as he goes!
Anticipation is a good place to start, if he knows it is coming it builds the excitement more. Look into his eyes and kiss gently down his body, let your fingers trail over his body, resist the urge to go straight for his dick though, if he is laying below you as you move down his body let your nipples brush against him, not only will this feel great to you but for him also. As your chest reaches his cock press down slightly letting him sit between your breasts as you suck and kiss his belly. This will drive him wild.