I have a 2 year old pitt/sharpi mix. She is extremely smart and loving to my boyfriend, my parents and me. To strangers she acts scared and aggressive. I rescued her at the age of 1 year old and don't really know if she was socialized properly. When we are out in public.. at the park or something, she acts very defensive. She doesn’t lunge or anything like that but she does bark, growl, get really tense and her hair stands up… but she doesn’t hide. Most of the time she wages her tail while doing it but not all the time. She also doesn’t do it to everyone... but not just one certain 'type' of person either. I have been giving her tiny pieces of hot dogs when someone walks by to distract her and it seems that it has helped her a lot. Also, she is fine around other dogs.. I was wondering if anyone had any other suggestions for me. I love her to death and am willing to try anything to make her more comfortable around strangers.

First, I hope your dog is well trained while being on the leash.
If your dog is well trained while being on the leash try the following.
You have to be alert to your dog's behavior. While on your walk if you feel your dog tense up, break away from the direction of your walk maybe, turn 180 degrees and go in the opposite direction. By doing this action it should calm the dog down and then at that time you reward the dog.
You do that whenever your dog tenses up, be it with people or other animals. You will probably have to repeat this action a number of times. There will come a time when you will not have to reverse your direction and when the dog is calm without you turning make sure you give the reward.
As for a dog's hair standing up. The dog might just be displaying excitement. For people it's hard to tell why the hair stands up. unless of course you are very in tune to your dog.

Also be advised that tail wagging is not always a friendly gesture. It actually denotes excitement, not necessarily happiness. If the tail is held erect and stiff and is wagging in small arcs or just kind of vibrating, this is a sign of aggression and dominance and means the dog will probably attack if provoked.

I heard of one lady with the exact same problem as you have who took her dog every day to sit on a bench out in front of a grocery store.

The dog would get corrected every time it showed any bad behavour.

Eventually, she asked strangers to give her dog a treat (most people agreed to do it) which let the dog know that not all strangers are bad.

The behavour problem & aggression towards strangers was fixed as a result of her doing this for a few months.

Good Luck with your dog!

These are all very good suggestions (actually, I would have gone over a few of them myself if the others hadn't saved me the time, lol), so the only thing I can add is try really hard not to correct your dog for growling and other warning signs that she might bark. Sounds weird and believe me, it's actually fairly hard to do. The logic behind it is if a dog is thinking about biting me- whether it's out of fear or true aggression- I want to know about it so that I can back off. If you tell the dog "No!" every time she tries to warn other people off, eventually she's not going to do anything and will just simply bite if she's provoked. I work at a pet hotel and I can't tell you how many times I have either been bitten or almost been bitten by dogs who didn't give any warning signs. I've learned to err on the side of caution more than I would like to, but people out in the real world won't necessarily do the same.

Basically, it sounds like you're on the right track and if you keep up what you're doing and even add in a few of the other suggestions, I think your girl will calm down in time.