I absolutely love eating pussy, and like the gentleman above said, everyone is a bit different. So, you do have to pay attention, to see how each one responds to certain techniques.
I like to start slow, and tease a bit. Either, kiss my way down, from mouth to neck, chest, stomach, just above the clit... or start at the toes, nibble on each one, lick under her calf, and kiss my way up her inner thigh until I get to the sweet spot.
Then, I tend to lightly lick, openining her up slowly with my tongue, getting her clit erect, and stimulated. I might suck on her clit a bit, almost like a little cock, occasionally letting my tongue slip out. Then sticking my tongue deep inside her, start almost fucking her with my tongue (which is also quite long, I can touch my nose and below my chin), as my tongue is fucking her, I'll rub my nose back and forth on her clit. I'll alternate between the two for a bit, judging her reactions. If she is ready for it, I'll start sucking her clit, while I use my index finger to reach her g-spot (like making the "come here" motion with my finger), this usually drives her over the edge.
If she still wants more... I'll start to work my tongue further down, and eventually to her ass, again I'll rub my nose back and forth, usually just touching her labia, so I'll bring my thumb up to her clit and rub it back and forth as I lick around her ass, and eventually penetrate her with my tongue.
Obviously the techniques vary with each, but hopefully you get the idea
And, its a bonus if she has a creampie!