One of the questions I often get asked is, “How do I train my dog to be off leash?” The answer to this is simple, although not as easy or quick as many people would like. The simple answer is to train your dog “on the leash.”
When you are off leash you have zero control of your dog and must rely on prior performance and habit. What this means is that if your dog does not do a behavior on a leash it is unlikely that he will do it on a leash.
The key, however, is to wean yourself off the reliance of the leash. Once your dog is reliably doing behaviors on a leash the next step is to get reliance when you have dropped the leash. It is amazing how much changes by that simple act of disconnecting. This however still gives you the option to pick up the leash is you need to re-enforce a behavior.
Try a short leash or tab, and finally moving to off leash. I always start in controlled environments like living rooms or a closed garage and slowly adding distractions to find out how much your dog can tolerate and still listen to commands.
Practice, practice, practice. The more you practice the better and more reliable your dog will be.