I use a pinch collar with a short chain ( about 6"- 12")and a old broom handle.
Atach the end of the chain to the broom handle .
Take the dog out and put the collar on it.
Hold the chain end of the broom handle at dogs head level say heal ,as you slowly walk .
DO NOT drag the dog.
If the dog trys to go ahead of you ,ajust the low end to stop it and keep it in the propper healing area.
In a few training secions it should have it down .
My lab needs a refresher every once in a while ( after playing with the neices)