Katy went though a little pulling period at about nine month.......
I used to make the journey of her choice very slow
Anytime she pulled I would say "oops". hold still and not move. When she looked at me or the lead went loose, I would praise, I would say "lets go" and start walking again. Now sometimes I would only get one step loose lead. And we would have to stop again and I would wait.
One day it took me half an hour to get to the gate of our kennel Club, where she was desperate to go, she loves it there.
If you feel you get pulled of your feet, just change direction. Same thing "oops" change direction and turn the other way. When the dog walks loose, you can go back to the usual direction. It takes a lot of patience, but it works and we use it in our Obedience classes.
Using a treat in hand is good to lure into heel position. But loose leash walking requires patience. I walk Katy on a flat collar, sometimes when I am walking all four I use her front attachment harness, It is fabulous for dogs that pull. Katy is really good 99% of the time, but gets a little excited when people talk to her from a distance, especially people she knows. So when i have all four we use the harness as a safety net. the other three are great and all were trained with that method. Even Lukey our new Rescue who pulled like a train and is now walked by a six year old.
Good luck Training