Gently pet or stroke them while they are in their cage. If they are really skiddish offer a treat and then pet them when they are eating. Sit on the ground and do the same thing. Don't attempt to pick them up until they come to you as you may spook them. If they wouldn't let you pet them, sit on ground with them and read to them so that you offer no threat. Most rabbits will become accustom to your voice and gradually come closer and closer,especially if you have treats. Before you know it they will be climbing on you.