You just need to understand how it works. I think it would be best to start off with a loose leash walk.
You need to get a 10ft or 12ft leash.
Obviously fit the prong collar correctly on the dog's neck and attach the leash. Pick a side for the dog to walk on. (i keep it the same every time i walk my dog so they won't get confused.) Throw almost all of the leash over your outside shoulder but keep enough for both hands to pull up on. (think of holding a baseball bat chest level.) Start to walk in a direction and has you feel your puppy stray make sure to correct with the collar at the precise moment. You need to be quick and on time so the dog understands who to follow. He/she will most likely yelp, but think of it as a cuss word from them. *&*# that hurts and i don't want it to happen again. Change directions slowly until you think your dog is getting it. walk in a "z" or a "square" or left, straight, left, straight... etc. once your pup understands he must follow you to avoid correction your walks will be much better. Once your pup understands what he needs to do you can try to bait him. Let him sniff the grass or look at whatever he wants to but change direction and correct right then for a good result.
I'm not a trainer but learned how to do this from one. It worked for me. Be gentle with the correction but get your point across. Your pup is only six months but he is stronger than most dogs for his age so you need to make sure he feels it. You should probably hear a little yelp..
Hope this helps.
Sienna Von Windtanz - At The Bridge
Pippa vom Germelhaus 12/31/2012