Ask your partner what they like!

Everyone is different; what works on one woman may not work on another. Some of us cum through clitoral stimulation alone, others need g-spot stimulation. Some ladies like fingers. Some cum more easily/harder in certain positions. Some of us can't come ten thousand times and want to be worked up to The Big One. Some clitorides (I embarrassingly just had to look up what the plural form of clitoris is; I mistakenly assumed 'clitori') become overly sensitive from direct tongue action and we need a sucking mechanism that allows the hood to cover the clit. Some ladies have really sensitive lips and stroking those helps us achieve climax. Sometimes stimulating the opening to the urethra is absolutely magical. The way to be the best oral maven is simply to ask!

I love a very soft, wet tongue lapping at my clit slowly. A lot of men like to suck on my clit and labia, but that's a bit too much for these bits. If you decide to incorporate your digits, make sure they're sopping otherwise it ruins the soft tease of the clit work. If you break away occasionally to kiss the crease just to the right or left of my kitty it's a real tease that will send my back arching.  

And there's nothing like a little vocal reinforcement to let her know that you like the way she tastes.  

Like the above ladies have said, it's all about finding what turns her on in particular. This is just the route to my orgasm...and a few of the ladies I've been with

Enjoy! xx

Practice, practice, practice then practice some more

Instruction and practice are both good and will get you where you want to be.  I recommend booking some two-hour sessions with providers you have seen before and tell them you want some guidance on how they like it the best.  Spend the first hour or until she can't have another O, practicing.