What are some creative ways to back out of a fight but make yourself look brave and triumph by doing so?

Depends on what type of fight it is. If it's just your average verbal fight, just say "Whatever, I don't need this" and hold up your hands and walk away. And if they call you a coward, just laugh and say "Yep, I sure am." I know it sounds lame, but it is how it has to be done. This way, you are letting them win without a fight and it makes them feel stupid.