Hi,
When I got a personal trainer to teach us how to manage Jack, he suggested a Choke Collar as shown on the left. It was effective but please do not use it with too great a force as you may break the dog's neck especially if it is a small puppy dog.
Subsequently, after changing it to many types of collars ( eg nylon, different catches .... I did not want to choke my dog..... a bit cruel, isn't it especially if it is well behaved), I found an adjustable choke collar. The difference is that when not tugged, the collar is loose unlike the typical collars. Importantly, the size of the collar can be adjusted such that it will tighten exactly to the size of the neck so it is not so much of a choke until the dog cannot breath but the message is conveyed to him. I hope you got what I am trying to say here.
Here is a photo of my Ruby, the Corgi, wearing an adjustable choke collar.
There are also all sort of leash but I have used this flexible or auto-release and recall leash which give both Jack/Ruby and I freedom to move about. This type of leash is easier found in the pet shop.