It is easier to walk on a harness - but the best thing to do is to teach her to walk to heal

I have found the best way to do this is REFUSE to move when they are pulling.
When she starts to pull stand still & pull her back to you & when she is close to you give her a treat.
At first you will find you have to treat every few seconds to keep her to heel, but then you can increase the time between treats to 1min then 2mins etc untill you only have to treat occassionally.
I start off with very yummy treats like ham & chicken cut up in to small pieces & when they are walking ok take a less value treats.
Once you start this you should never let her pull as it will confuse her.
This will not work overnight & she will have shorter walks for a few days.
It does work though if you are consistant,
All mine walk ok when out on their own - I still can not stop them pulling when out together so I put them all on harnesses!