Take your time during fights to get higher rankings. There is no penalty for taking your time to win. Build stamina and always have enough to evade attacks. To get a better rank, avoid getting damage as best you can. Avoid attacks that can be bypassed, and block special attacks. Getting the best possible rank will let you get more money, better items, and health regeneration. If your opponent uses a "raging" combo, block them instead of trying to evade three consecutive attacks.