The leash is a safety net. It is not a tool to make things happen. The ultimate goal is not to NEED the leash.
So, notice everything that you do with your leash.
Don’t pull your dog around with your leash.
Get your dog’s attention and convince her to do what you would like her to do without using your leash man handle her, or to force her. Use your leash as little as possible.
The leash is a tool, the word leash here can be substituted for any tool. (treats, head halter, etc.)
Be aware. Be curious. Be manipulative. Be convincing. Be grateful. Be strong. Be smart. Be in-charge.
I am not saying take your dog-in-training off the leash. I am saying keep the leash on but use it less and less to get your way, because the less that you do the more your dog has to do.
From: The Unwritten Book of Mostly Useless Ideas Pertaining to Dogs and Dog Behavior.