SWOSUMike

Make sure you just give "pops" on the prong collar and don't try to just keep it tight all the time. The dog will get the idea when you pop on it.
I don't agree with whoever said not to say the commands to the dog yet. I think you should say things to the dog all the time. That is how it will pick up on things and it happens without you even knowing it. Say the command often cause the dog will catch on to that.
Also if that doesn't work, get one of those things they call a gentle leader. It is like a muzzle that connects to a leash and the dog jerks his neck backwards if he pulls to hard. I think it is supposed to cause the dog to heal naturally for it's own comfort, which helps get rid of some of the dog's desire to pull when on a simple leash. I've never used one but it sounds good to me. If I ever decide to make my dogs learn heel, I will probably go buy one. As it is, I am fine with my dogs only knowing "come," "sit," "down," "load up," "kennel" and "wait." If you're dog can come, sit and wait while in the woods, you've got most of what you need from them. Heel is nice though if you are a birddog guy. Mine are treedogs.

RUFNECK

by giving commands you confuse the dog your teaching it to walk or heel the way i explained before will help once the dog walks then you teach it the command heel

SWOSUMike

Saying words to the dog will not confuse it. It will only create more association. The more you say something to a dog, the quicker they figure out what it means, especially if you show them what to do as you say the command every single time. To me, if you wait til later to use the commands, then you only create another tedious step. Do it all at once and the dog will catch on. They are not dumb and will not get confused if they have an ounce of trainability and a trainer who is consistent, fair, patient, and even-tempered. It never hurts to say things to the dog, especially commands. If you are going to make them do something like walk at heel, then you might as well say the command because before you realize it, the dog will know what it means. For example, my dog often rides shotgun with me instead of in the dog box. Sometimes when he was pup, he'd try to get in my lap, and sometimes if I left him in there for just a second he would wait for me in my seat. Not even realizing I was teaching him something, I just started saying, "Get over" every time I wanted him to go back to the passenger seat, and I would sort of push him over there. Now he knows what it means and I didn't even set out to teach it as a command. It would work the same on the "heel" command and any other you teach.

porknbeans

Pulling on a leash in a dog is an indication that it doesn't see you as the leader of the pack. However, for a 5 month old dog there is a great deal of ...well, just being a puppy too. I use Delmar Smiths wonder lead on my dog and believe in the Silent Command System. The first thing that it teaches is to make you the leader of the pack. Not in a brutal way, but humane. For a 5 month old pup, I agree with using a half hitch. I used it on my dog when she was that age. It maintains control, is not harmful to the dog and begins to teach the dog that she can't do everything it wants when it wants. Good luck.

RUFNECK

lets get some things straight here
1 im not saying not to give commandsfor all training and yes i am saying you can and probely will confuse your dog by talking while TEACHING him to walk if your not confident or do not have knowlege in training
2 by teaching the pup to walk before training him to heel (yes there is a difference between teaching and training)you can have a better handle of your dog when it comes time to train to heel by teaching him or her to walk before training to heel you will cut down confusion
example when you dog is on the leash close to you you should not have to command it to walk with you but when off the leash or in the field you want to be able to command your dog to heel the difference is when heeling the dog should be at your side standing erect and to the side you train him or her to heel too usally the oppisite of the side you carry your gun when walking your dog should be able to walk on either side to find somewhere to go to the bathroom if your dog is taught to walk with the heel command the dog becomes confused when just walking it may want to go to the right side to find a good place to use the bathroom then the left to go again
solets sayyou teach the dog to walk by training him or her to heel then i guess you dont give the command to heel when the dog needs to got to the bathroom so being the dog was never trained to walk without the command the dog dosnt know not to pull and be aggresive while on the leash make sense
3 after you teach your dog to walk you put your dog on a 25ft check cord let the dog go then when you want him or her to heel you give the heel command and pull the dog in and to the side you want it to heel to now that your dog knows how to walk you keep light tension on the collar and walk. the dog will allready know to stay close ,then stop reward the dog and repeat after 3-5 times put the dog back on the regular leash and take it for a walk after a few days start with the command give the dog a chance to heel before pulling it in when you feel the dog knows the command and understands what to do start heeling then walk stop switch directions and other movements without talking this will teach the dog that its on heel till you say otherwise if the dog makes a mistake dont yell or disipline verbally jerk the chocker then realease the dog command to heel then star again

there is many methods of training that work this is the one i like because it is easy and effective ive trained my dogs and friends dogs to walk and heel in as little as 5 days and never more than 2 weeks
not trying to make conflict just trying to clear up what i was talking about every one has there own style and im sure most of them work
good luck with your dog