Well, here's what worked for my hubby with Chopper. First off, he worked extensively on his "watch me" command. He uses a prong collar on Chopper and when he started to get distracted he'd pop the collar "watch me!" Chopper is very food motivated to treats helped too.
There is this one house that has three rowdy dogs that always got Chopper fired up. Instead of avoiding the house, Scott would purposely walk Chopper by there (on the opposite side of the street mind you) to work on his distraction. They did this for months. It was not an easy overnight fix.
Chopper is also not a dog that you can train once and he's fixed. Everyday is a learning experience with him, and some days are a struggle. Living with a dog who's dog aggressive, you always have to be on your toes. You cannot fix it, but you can learn how to control it. Best of luck to you!