I have two feral cats adopted at different ages and time cuddled up with me right now.

One was found about 4 weeks of age. He is about 8 years old now. The other moved in at around 4 month's old, she is about 3 years old now. She only stopped acting feral and turned into a cuddly cat a few months ago.

When you finally manage to earn their trust is the greatest feeling.

Give them food and make sure they see you giving it to them. Sit in view of the food bowl. Move the food bowl closer to you daily. When the food bowl is right next to you, bother them by touching briefly. Do this until they no longer get scared of the touching and you can pet them for prolonged times.

This might be weird but you might want to separate kitten from mother to work solo with it as the mothers fear or hate to people can be learned quickly by the kitten. Older cats are also a lot harder to get tamed.

Source: I have two 8-12 week old kittens in a spare room and am working with them daily. I found them in my crawl space a week ago and took the mother to the vet to be fixed and let her go. They make progress slowly as they learned to be afraid of me from their mother.