At first my BB do this to!
Make sure it's to loose or tight. Usually I set the leash as the same height as my hip.
When she walk in front of you, stop, stand firm, and snap the leash (not tugging it), say "NO".
If she has learned to sit, tell her to sit.
Then you can walk, but keep her walking beside you. If, she did it, praise her. If not, repeat the first instruction, changing direction suddenly can help too.
It'll take time and a lot of patience, hope this will help
If you still face difficulty, I suggest you to look for profesional help.