To help a fearful kitty, the best thing you can do is to give that cat a safe room to call home, go slowly and be prepared with a lot of great food motivators. The old school thinking of “tough love” for fearful kittens has been replaced by a much gentler, rewards-based interaction. And the proof is in the lasting relationship you’ll build with your fearful friends if you build their confidence by letting them make the choices and keeping their fear at a minimum.
Sit with them, talk to them, offer some really great, tasty food motivators as a reward for every brave thing they do, and eventually you’ll find a more confident cat who feels safe with you because you didn’t push them to interact solely on your terms!