Written by Emily Nagoski, Ph.D.
To begin with, remember that the perception of sensation is context dependent, so that a sensation that's sexy in one context will be annoying or even painful in another. What qualifies as a sexy context varies from individual to individual and couple to couple, but in general they involve trust, respect, a fair degree of privacy, a lack of stress, depression and anxiety, plus a sense that your partner desires you.
So step 1: create a sexy context, whatever that means for you and your partner.
Step 2: Soft and slow.
No, slower than that, and softer than that. Just barely touch your lips to whatever part of your partner you're kissing; kiss them more with your breath than with your lips.
Then bite that part. Not too gently.
Travel to a nearby spot and repeat, incorporating judicious use of tongue (wet skin + breath = good) as desired.
The focused attention required is, in and of itself, good technique. What you do matters less than that you are paying attention to your partner and enjoying shared sensations.
Whatever you do, do not wipe your tongue like a paintbrush over your partner's gums, inner cheeks, or the roof of their mouth. Your tongue goes between their lips in pursuit of their teeth or their tongue and for nothing else.
And don't, for the love of mike, press your open mouth into theirs so that both of you bash you lips against your teeth. Pressure does not equal passion.
And finally, don't CHEW on your partner's lips. Nip and suck, absolutely. But gnawing on your partner like a dog on a bunny just does not cut it, friends.