For the uninitiated Jin Shin Jyutsu is an ancient practice, or rather art, that teaches how the energies of the body can be harmonised and tensions released. What this practice does is enable a person to tune all the energies in the body to balance oneself physically, mentally and spiritually.
Jin Shin Jyutsu propounds this by a very simplistic method. It says that every finger is connected to various organs and parts of our body and also controls our emotions.
It believes that holding a finger correlating to the emotion you want to calm or the organ you want to heal helps one to restore balance. If a finger is already pulsing then hold that finger till the pulsing slows down. You could also hold all the five fingers till one starts throbbing strongly and then you can calm that down.
Another way to do this is to hold each finger for two or more breaths. This can be done daily and has proven to be beneficial to one's mental and physical health.
Holding the fingers before one falls asleep has also proven to be an excellent practice. This self acupressure will also enable you to sleep well. You can read more about this here.