The primary key to effectiveness in a real fight is AWARENESS, followed by your particular skill sets.
What do I mean by awareness?
- Does he have a weapon or maybe has one? Does he appear to be trained on how to use it? If a gun is right to your temple, he hasn't been well trained vs. keeping their distance, etc. With weapons, avoidance is best unless you feel they are intent on using it and you're not in a position to run (need to protect family, etc.)
- Are they just posturing and huffing their chests, or, do you believe an attack is imminent? If imminent, you better strike first. If not, perhaps you can diffuse.
- What are your immediate surroundings? If on concrete or asphalt, I'm going to look to slam and use the ground to F them up. If on grass, I may Arm drag to back - but I'm not doing that on cement, etc.
- Are they big and strong? Weak and fast? Both? Do they have cauliflower? These are factors that lead to strategy.
What are your skill sets?
As a Brown belt with a wrestling background, I can do well in almost any position, but, I do prefer top, followed by the back. If weapon, can i disarm/parry and smash with my basic weapons defense? I'm more scared of a knife than a gun BTW. Your skills will factor into your approach, but, awareness and environment is equally important if not more so. Depends on "who you are" and what training you've had.