Pulling

I just come back with my cross staffordshire from spending day in park festival. She is 1 year old and i have trained her to walk next to me with a "slowly" command and tapping my leg. She tends to obbey a lot better unleashed than otherwise but still today was a very hard all day pulling. If I was letting her loose she would walk away distracted by everything.
She was very distracted by crowd and food/people eating.
Now, today was a extream situation, there was loads of people around, but she does still do it. She is very friendly and approaches anyone. This is luky in some way (she is a sweetie), but it can be dangerous for her 'cos she might get lost, stolen, or run over by car. She hurted herself today from pulling so much and has come back with mark from the harness. Other times people react badly to her coming next to them (this is another issue, they have a problem, cos she doesn't jump on people just aproximates wagging her tail).
I have to say that sometimes I feel she would go with anyone else, she doesn't demostrate an special attachment to me, why?. It is like I amnot her master but her carer, what it is not the end of the world, it hurts me but, it mostly worries me when she is not safe.
I have heard of having them only called by their master, of "training collars" (this looks harsh to me), what can I do?

Every time she tries to walk in front of you even if she is not pulling stop and make her come back to your side and dont move until she does. Then once she is at your site give her a little rub and start walking again. Repeat as needed with dogs walking in front is being the leader so you should always be the one in front "in charge"

Is there a special reason you use a harness? I just ask because a harness makes it much easier for a dog to pull - that's what they're designed for, after all.

I've read that many dog-fighting breeds were deliberately developed to be very easygoing about changing owners, because in their original careers they were swapped and sold quite often.

Apart from possible breed influence, she's a teenager. They're flighty. When my dog was a year old, she'd have jumped into any car going and been in California before remembering me. She once got out of the house and when we found her, she was cantering cheerfully toward the horizon. They're wonderful at this age, full of life and energy and joy, but they're a few years away from being steady, loyal dogs. She's still just a puppy in many ways.

lol. because she's a bully! they're social butterflies. my luce is exactly the same way. i understand feeling hurt by it. sometimes i feel like i put in SO much effort with her and she thinks everybody else on the planet is way cooler than i am. brat.

Thanks

Yes true better with a normal collar than a harness! Thanks everyone for replays. Training in progress again, it looks like we are going to be patient with this one! and firm!