It really all depends on the type of woman but most women will enjoy some small variation of what I am about to say. If they don't then I am stumped.
Take your girl and kiss her gently. Work her up to it. Kiss for a long time. Not too long but until you feel her breathing harder. Make sure to use your hands the whole time. At this point, keep them above her neck. Probably one on the back of her neck and the other in her hair. After you really get her worked up, lay her down and move over her, still kissing her gently. Slide your hands down the sides of her body. Don't just go for the obvious spots. Slide your hands over her arms and touch her hands and fingers. Slide back up and move down the sides of her body again. Run your fingers over her stomach gently and then down over the tops of her thighs. Slowly bring them back up now and gently caress her breasts through her shirt. Kiss down to her neck now and keep it gentle. Give her light kisses and licks over her neck slowly while you caress her breasts. After you think she is ready to go a step further, slide your hands down to the hem of her shirt and slip them under. Touch over her bare stomach and see how she reacts. If she seems to like it, then slide them up and feel over her breasts again. If she isn't wearing a bra at the time, just go right to teasing her nipples gently with your fingers. Trace around them softly and them give them a light pinch. Nothing that will make her jump though. After a little bit of this, slide your hands out and start to take off her clothes. Take off her shirt and move your kissing to her collar bone. Lightly nip on it with your teeth before sliding down between her breasts. Kiss under them and over them first. When your mouth is on one, use your fingers to mimic the motions of your mouth on the other. Eventually start to kiss her nipple and lick it gently. At this point, you need to gague what she is into. If she seems like she would lick a little rougher play, then go for it. After paying attention to her breasts for a while (and also making sure not to let your hands go idle!), make you way down to her belly. Kiss every inch of her. Lick around her naval and tease her while you open up her pants. Take off her pants only. Leave her panties on. Kiss down to the waist band of them and then veer off one way or another and kiss down over the top of her thigh. Make your way to her inner thigh and kiss her gently. Use your hands to move her legs where you want them if she doesn't do it for you. Never touch her between the legs yet. You want to build up the antisipation. Kiss all the way down to her ankle and then make your way back up. Do this to both legs. Make sure you take your time because the longer it takes you to do this, the more anxious she will be to have you touch her in more desired areas. Finally, once you've teased her enough, touch over her lips through her panties. Rub very gently and then kiss there lightly. While you do that, start to remove her panties. Once they are off. Spread her legs and kiss along her inner thighs again but stay close to the top. Don't get carried away and forget the goal. Make your way upwards until you reach her lips again. Kiss and lick over them slowly. Once you have her going crazy under you, use one hand to part her lips gently. Start by licking up and down the entire area. Taste her and maybe, if you think she's into it, make a couple of noises to let her know how good you think she tastes (a lot of women are self conscious about themselves in that regard, so let her know if you like it!). Press your tongue into her opening a bit but don't do this more then a couple of times. It's not where she is going to get the most pleasure. Move up and start to gently lick over het clit with small laps. Don't apply much pressure to it just yet because it will be sensitive to start. One you work her up to it, apply more pressure with your laps and then press your face down into her. wrap your lips around the clit and around a bit of the surrounding area and suck gently. Use your tongue while you do this. At this point, you will again need to figure out what your girl likes. Some women need harder stimulation where other women only need light touching to get off. You need to find this out either ahead of time or while your down there. Start off gentle and if she is bucking up against your face, you know to do it harder. She'll let you know if it's too much with her noises. Listen to her while you are doing this. After you figure all of this out, don't move away from her clit. This is the difference between men and women. You can abandon the penis mid blowjob or handjob to do something elsewhere and then go back and the guy will still be able to cum. With girls, they need constant stimulation. The biggest mistake men make is to go down and start licking the hole again. Forget that, just keep your tongue on her clit. This is where your free hand comes into play. Slide two fingers into her, palm up and curl your fingers in a "come hither" motion. When you feel your fingers rubbing on a textured area, you know you've found her g-spot. Either that or she'll be moaning a lot more. Either way, you'll know. Rub that spot while you suck on her clit. She'll come in no time. Hope that helped some of you guys out there who didn't know how to properly go down on a woman. Enjoy.