A great leash and harness is the foundation for successful loose leash walking. You want a harness that is comfortable for the dog, but still snug so they can't houdini out of it. I like to have at least two different length leashes. A standard 6 ft. leash and at least a 15 ft. leash. Long leashes are great to practice recall and to give your dog freedom without the worry of them running off.
Remember, the width and weight of your leash should be proportional to the size of your dog.
6 foot Leash w/ Traffic Handle
Any 6 foot leash will do. I love leashes that have two handles. One at the end (the normal place) and one closer to the dog. This is great if you need to bring your dog in closer to you.
Waterproof / Biothane Long Line
Long leashes are a great way to give your dog some extra freedom without the worry of not having a 100% reliable recall. I like to get ones that are a rubber material because they are easy to clean.
Ruffwear Front Range Dog Harness
Chest size range: 13 - 42 inches
Front and Back Clip
Freedom No Pull Harness
Chest size range: 15 - 44 inches
Front and Back Clip
Hurtta Razzle Dazzle Y - Harness
Chest size range: 14 - 40 inches
Back Clip