Who can be hypnotized?

Pretty much anyone. Unless they don't want to be—or maybe want it too much. The idea is to relax. Let your conscious mind drift off.

You can't be hypnotized to do something against your principles. Your conscious mind is still present in hypnosis, it's just in the background.

And each time you experience hypnosis, the easier and faster it will be to go into a hypnotic state the next time.