At one point, she started biting when I would pet her. "No!" Didn't work, So the 3rd time she did it, I hissed at her. Not a growl or spit, but just a "hhhhhhhhh!" She jumped up, gave me a startled look, then turned her back to me, a sign of respect. About two days later, she tried to take another taste, I hissed at her again, she jumped away and shook her head. She has not tried it since. Now when she wants to grab and bite, instead she will take hold of my hand and start licking me.
My one cat ran around my house for several years as a feral. He would only show up at dawn/dusk, would hide in the bushes and was unapproachable. One winter morning he was sitting on the back step obviously quite ill. I was able to scoop him up and get him to the vet. That was five years ago and this autumn he has decided he likes laps for the first time. We worked through his deep-seated wild fears, but it has taken months and even years to get to where we are today with him.