I found my pitbull mix pup as a stray about a year and a half ago, we believe she's currently about 2. When we first introduced her to my parents dogs, we did not have any issues with her, if anything she was the underdog. She has shown an aggression toward new dogs lately, sometimes actually snapping at them rather than just letting a little growl out (never actually biting them though).
I have socialized her a lot and she gets along well with dogs she has been around a little while and gets to know, but I am at a loss as to what methods I should try when introducing her to a new dog. I take her to the beach a lot since I live 5 mins away, and while I have a leash on her around people/dogs, I leave her loose as long as it's pretty empty. I always trust her to run back to me when I call and not run after another dog if one shows up, but sometimes loose ones run up to us.
Any advice would be appreciated! If there's anything I left out that may give someone an idea of what I should do please let me know.