Dog harness help please...?

Hello, I just rescued a border collie/Shepard cross?? from my local shelter. Long story short she wanders and pulls on her leash. She is barely 1 year old if that matters I don't know. Anyway I am trying to teach her to walk nicely or to jog in a straight fashion so as not to trip over her. I haven't any experience with harnesses. Will this make training her easier? Is there a specific type that works better than the next? I looked about and there where many styles. I really have no idea where to start. She is a medium sized dog 45lbs give or take. Small feet an doesn't look like she will grow much bigger. I would appreciate your help.