Pulling On The Lead?
The easiest time to teach them not to pull is to teach them as puppies that by being with you is the best place to be. Often, it is only when folk have a problem, that they seek further help.
So why do they pull?
What some people fail to understand is that if their dogs lead is always taut, they learns to pull because pressure produces counter pressure.
Try it yourself with a lead between yourself and a friend, if they are holding their end taut, it's a natural response to pull however once your partner has eased up on the tension, you will also not feel the need to hold it so tightly.
Loose lead training is the way to go forward, using lots of positive reinforcement, It will take you longer to go a shorter distance, but consistency in their training will pay off in the long run. Training aids, such as head collars and harnesses are also recommended especially if you have a 'serial puller', as pulling on the lead can cause damage to your dogs larynx, neck, back, hips, knees (as well as your own of course!).
Please bear in mind, these injuries can also manifest in small dogs, so don't be fooled into thinking that just because it doesn't hurt you, it's not hurting them. When a dog is in pain, they can be more sensitive when being handled and may not want to move from resting, and may be more likely to snap and want to be left alone, and it can be so easily prevented if you try to nip the pulling in the bud.
Tackling this problem does take time, consistency and patience, however it will be worth it in the long run and make walking more enjoyable for both of you.