Rest - This is ostensibly the simplest component as it literally involves doing nothing. However, getting the proper amount of rest is a very important part of any training program and overtraining can be very detrimental to your gains. A general rule of thumb to follow is to allow at least 24 hours of rest in between working the same (or similar) bodyparts but listening to your body is probably the best thing to do in order to determine if you need more rest. Signs of overtraining can include fatigue, delayed muscle soreness, eye twiching, and more.