Good advice there. Yeah...I would let him practice in the house with just dragging the leash around (supervised) and play with him, give him a treat or two....just to associate the leash with a good time. Then go outside and do the same thing. Then, without the leash on, encourage him to come along with you, don't face him, but trot along yourself, clapping your hands, making squeeky, fun noises, drop treats along the way. Make it a game. Do that several times for a day or two. Then attach the leash and do the same thing. Just let him drag it. Don't hold it yet. Make it lots of fun and rewarding....a slightly hungry tummy and some extra yummy treats or a special toy, just for this occasion is helpful. Then pick up the other end of the leash. Never pull, force or cause tension, just encourage, entice, reward. This has to be associated with a great, fun time.
Next, start rewarding ONLY when he is near you and not when he goes off on some other direction. Praise and let him know what you like. You can use a "marker" word or look into clicker training and use a clicker. I sometimes use a clicker or if I don't, I use the word, "yesssss!" It comes JUST at the moment the dog is doing what I want, not after, not before. And then the reward. The idea is to first PRIME the dog by using that word or clicker, followed by a treat in random places around your house. The treat comes right away. The dog is not doing anything in particular during this priming stage. After about 10 minutes you'll see that he's beginning to associate the marker sound with getting a treat when you use it and he looks expectantly at you. Then take it with you for your training sessions. He walks nicely, "yessss!" Treat. He strays or pulls, stop...don't reward him with going where he wants, don't do anything else. When he comes near you again, "yessss!" treat and resume walking. He wants to go, so if he isn't going WITH you, that reward of going forward is removed until he comes next to you.
The idea of the marker is that sometimes we don't get the reward to the dog at the precise moment he's doing the behavior. So the marker lets him know that THAT IS the behavior we want and he's going to be getting a treat. You need to treat asap after the marker sound. So for example: if you're teaching a dog a formal heel, if he takes two steps perfectly but then strays, by the time you get the treat to him, he may have stopped the perfect steps and has begun the not so good steps and you're rewarding those. It's just more precise and lets the dog know what exactly he did to earn the reward.
Anyhow, I recommend looking up clicker training because the concept and method will be described so much better. It's VERY effective and fun.
http://www.dogpatch.org/obed/obpage4.cfm
