Stop worrying about technique, or hygine, or taste, or really anything you're worrying about. All you really need to KNOW is that your mouth + his cock = Male Brain Overload. Think of it as being on par to him giving you chocolate and a really passionate kiss. It's THAT intense and romantic and beautiful, only it's a guy-brain kind of romance, a guy-brain intense, etc.

Try your best not to hesitate. You don't have to deep-throat him if you can't, but by all that's holy, don't act like the thing's going to bite you. You stick it in your pussy just fine, don't you? Why the hell worry about your mouth? In and out, try not to bite, use plenty of tongue... oh, and swallow often. This helps YOU a lot, making it easier to keep going and keep breathing, and it feels pretty good for him too.

If you really can't cope with the idea of putting one of your favorite parts of your boyfriend/husband/whatever's body into your mouth (and there are therapists to help you with this honey, it's worth learning to like, trust me) then you might at least be able to lick it. They like this. A LOT. Start at the base, lick the balls a bit, and just lick your way nice and firm and greedily up the shaft. You liked popsicles as a kid, right? This is no different. Think of it as the Popsicle Of Love.

Orgasms are important. Remember, a guy often only gets one of these a night, unlike us lucky girls who can get quite a few if we go about it right. If you want to fuck him, you might not want him to cum during the blowjob. If you AREN'T going to fuck, don't even think about starting a blowjob you aren't willing to finish, it's just mean. Talk to him before you even start, find out if he hopes to have you swallow or wants to cum on your face and decide ahead of time what you're comfortable with, so there's no confusion halfway through; if you know what to expect and he knows what to expect you're unlikely to end up with cum up your nose.

Swallowing is actually not that hard, particularly if you have him deep in your mouth. The further back the head of his cock is, the less you'll taste what comes out of it. On the other hand, if you aren't worried about the taste, catching it right on the tip of your tongue can be nice as that's the part of your mouth that registers sweetness, and so tastes the sugars in his cum and really enjoys them. If you aren't going to swallow, have a towel or something handy, don't make a big production out of spitting. Just do it and go on. If he cums on your face, in your hair, or wherever, remember that with those sugars and proteins, cum gets sticky! Be ready to wash it off fairly quickly or it WILL stick to freaking everything and be a pain in the ass to deal with the next morning.

Ways to make it easier on him: none. It's a blowjob. Seriously, all he has to do is sit comfortably (sitting in the middle of a sofa is good, with you kneeling on the floor, his legs spread nice and wide, leaning back with his arms either at his sides or up along the back of the couch) and as long as you don't bite or throw up on him, he'll be FINE.

Ways to make it easier on you: Feed him plenty of fruit and things with vanilla extract in them. Swish a nice mild non-citrus juice around in your mouth just before going down on him. Make sure he's showered recently and has at least some idea that washing his naughty bits is Important. Pause to breathe when you need to. Use flavored lubes or even just a little bit of chocolate syrup, fruit jelly, or other nummy substance to make his dick a bit more edible. Don't worry about doing it right or wrong, he'll be thrilled that you're trying and the more you try, the more you'll start doing what he likes just naturally.

One other important thing, after you've gotten past the first time or two and have started getting comfortable with it: encourage him to talk. Things like "deeper", "lick the head a bit", "ooh, do that again", or even just happy noises when it feels particularly good, anything to help you learn what your particular boy likes. Every man, like every woman, is a bit different, and the best way to please yours is to get comfortable enough to be able to learn what he likes. Plus every time you practice, it's Brain Melty Happy Time for him, and afterward he'll be more than eager to make YOU just as happy.