We are almost done with puppy headstart. We only have two weeks left. Anyhow, we use a harness with Esme, and I would never use a leash on her tiny neck because it seems so delicate! Actually, the breeder recommended using a harness too.. A harness is perfectly fine for training. It's the same as using a collar pretty much. Anyhow, when we started the puppy classes, she was 12 weeks. She finally started willingly walking on a leash last week. So it took about 5 weeks for her to get used to it. We did although only put her in the harness and leash on Sundays when we go to petsmart, puppy training class and Einstein Bagels.
) So, I guess if you are more regular about doing it daily, it'll go faster. At first, we walked around the house with it. And then my husband would call her to follow him and I would walk behind holding the leash. It's funny because now she tries to run with the leash on and it's halarious because her feet are going but she isn't moving as fast as she would like!
We also give her treats for not pulling (like I said, she likes to pull).
Good Luck and Have fun!!!!
Mari