Now about which hand to use, well I have two theories on this. You can either use the hand that you don't write with, the reason for this is, lets say your like me, your left handed, so my left hand would be stronger than my right hand, so if I used my right hand I would have less conscious control over the pendulum, which is what you want.
The other theory is to do with subconscious and the right side of the brain. The subconscious is the part of the brain/mind, which deals with all the psychic phenomena and spiritual contact, and also the right side of the brain is connected to the left hand side of our body, so in this theory we use the left hand to hold the pendulum. I've experiment with both and I find this theory is the more accurate for use with a pendulum. I've done a lot of experiments in this area with hypnosis and found it to be a fact. Try both to see which is best for you. You will have and advantage if you are initially right handed because you will be using your left hand, the weaker one, plus the subconscious. You can also apply this theory to anything, whether it be choosing tarot cards, runes, automatic writing etc. Another important thing to mention is the sceptics, they will often say "Well Its the Subconscious which is moving the Pendulum" and that's correct it is the subconscious, but that's exactly what you want to happen, like I said earlier its the subconscious part of the brain/mind that deals with the psychic and spiritual communication.
Ok, now we need to establish some sort of YES and NO method to use with the pendulum. We need to program the subconscious to recognize a YES and NO response. The best way I found in doing this was to consciously start the pendulum moving (make it swing) in a clockwise motion and while you are doing this you can mentally or out loud keep repeating the word "YES" over and over. Then do the same for the NO response, but this time consciously swing the pendulum anticlockwise. You may need to do each one for about 5 minutes and leave a few minutes between each response. You can also try it the other way round too, anticlockwise for YES and clockwise for NO, again whatever works best for you.