Let go of all those negative thoughts, because the answer is you are beautiful and you need to realize that. You've probably heard the saying, "Beauty is in the eye of the beholder" and while society might have their standards for beauty, you don't have to conform or believe them. Think about it this way, would you rather listen to someone who's telling you you're not beautiful (society) or someone saying you are (your significant other)? The someone saying you are, right? Also, don't confuse your inherent beauty with your genitals' lack of beauty. In other words, you are not your genitals; they are just a part of you. Maybe their lack of beauty is why you should put them in each other's mouth's more, so you don't have to look at them. I mean, if I had to choose between looking at my partner and looking at my genitals, I'm going to choose my partner.
Also, if your partner gives oral then you need to reciprocate, not necessarily in the same session, but relatively soon. Ok, time to get into the more technical tips.
#2 The Wetter the Better
Now, this may just be with blow jobs, but it could also work for going down on that pussy. Not only does making things wet help with the lubrication, which ultimately makes everything easier, but the sounds that come along with it can bring the experience to a whole new level. If it's time for a blow job, try spitting on his dick and giving it some nice hand action to spread your saliva all over before taking it into your mouth. As crazy as that sounds, it works for most guys, might even drive them crazy with desire for you.
It's no secret that genitals don't exactly taste like crème brûlée. The good news is flavored/edible lube is a great way to make things tastier so the giver can have a delicious experience. Plus, there are so many great flavors to choose from like Intimate Earth's Banana Cream Pie & Salted Caramel to Wicked's Aqua Cherry & Vanilla, plus you can't forget about Shunga's Tangerine Cream. Also, if you're going down on someone, make them squirt. Now, this may require some fingering so the g-spot can get some love, but this will be the oral they never forget.
#3 Find the Clitoris / Play with Balls
If your partner has a clitoris, make sure you know where it is, because that's going to be the spot you want to focus on for oral, otherwise, they won't experience nearly half as much pleasure as they could be. If you're already a pro at clitoral stimulation then you might want to add in some fingering or massage their breasts. Depending on your position, you might want to grab their butt, or if they're into anal, stick a finger in that booty.