I have found a few things that you must know about.
My big guy, Flash, is a real challenge for me. First of all, he is hunormous. (yes, that's a word) So when I take him on a walk we usually do it off leash. He is extremely obedient and there is a nearby secluded area that we like to frequent. When I get him on leash it's a freakin' circus. He is a tugger and I prefer to verbally command him than physically try to fight with him. He also has a habit of barking when he is nervous or being bossed.
Here is my fix.