Pulling on a lead

This is the technique to teach a dog, from puppyhood, or from an advanced age, how not to pull you on his leash, when you are walking him.

Always keep the dog on your left side. Step forward with the left leg, in a cheerful voice, saying "Let's go!"
As soon as the lead goes taught, say "HEEL!" and jerk the lead. S/He will stop. Say "Good boy!/girl!" and then step off
again with your left foot first, cheerfully saying "Let's Go!"
Alternatively, simply stop walking when s/he pulls - stand still until the lead goes loose - it will eventually! - and then
continue. It takes some time & patience, but all dog training does & it works. You'll end up a dog who walks happily at
your side
Don't let them actually stop. S/he is making to stop but you keep walking and praising. What you are praising is the fact
that s/he is breaking his fast stride on the word "heel."
Never say Heel more than once per decision to heel.
If you repeat Heel too many times s/he will ignore it...it will become white noise to him. Instead..say Heel once, if s/he
doesn't alter his quick pace, sharp tug on the lead.
Don't "punish" your dog. Positive reinforcement (the praise and treats) is key to success.

Don't over train. End the 15 mins on a happy success moment. Don't end it when s/he is screwing up. Set the bar lower if you have to, in order for the session to end after 15 minutes maximum on a successful note.