Training my dog to heel properly?

I relly don't think you need to go straight to a prong. I taught my dogs OFF LEASH to heel with food. I started with the dog sitting in heel position. I would give the command to heel- and take ONE step. Keeping their attention with the food. I was able to slowly do away with the food, as this became muscle memory. I went from 1 step to 2. From 2 to 4, etc. When doing longer heeling sequences, I used either a hot dog, or string cheese, and the dog was allowed to nibble as long as it was in heel position. When out of position, the food went away. Worked like a charm for me! My dogs are smart enough to know when the prong is on, and when it's not. So, by reinforcing the behavior I wanted, I didn't ahve to rely on the prong.