Clinton Anderson. Check him out on youtube!
PLEASE, my forte is horsemanship.
I'll give you some key basics to really look into before lunging a horse.
Also How old is your horse, and what training experience am I working with?
1) When you begin lunging a horse I highly recommend getting a lunge line. If you are not sure what you are doing with the horse in an enclosed circle, you don't want to be with a horse that doesn't realize you don't know what to confidently do.
2) Body position while facing the horse. When the horse is standing with its whole left (or right) side flat in front of you, position yourself where your left hip is parallel with the horses front shoulder. Use that leg to pivot on. Keep your hip (closest to the horses back hip) just a slight bit facing their barrel more.
3) Now, if you use a lunge whip- do not mistake "go" with "*Crrraaccckkkk!*"
4) Use your verbal commands first. If the horse does not respond, wave your arm closest to their behind, and give a stern command. If that doesn't work, use voice and arm signal. Now, with your lunge whip in hand, tapping the horse on their butt while saying command is acceptable.
5) Always begin with contact. Don't let the horse be so far away from you that they drag you wherever.
6) Don't let the horse be so close to you that if they get confused.... well- bad things can begin.
Now, after you get the basic Proper* way to begin a lunge session, now you can ask your horse to walk, trot, and eventually canter.
Lunging should be about horse-human communication. NOT lunge the horse till all his energy is out!
I recommend watching videos such as these to help you progress:
(Hope my advice helps, msg me if you need :])