Aside from just being good at dueling/blocking/feigning which is what naturally comes to mind, intelligent decision making and situational awareness are also important. Can you learn these things in a direct way like blocking/feigning, maybe. Especially if your struggling playing battle or something it really doesn't matter how skilled a fighter you are if you make stupid decisions. Getting tunnel vision on a guy your trying to kill and getting lead into a mob of enemy troops isnt good.
Always prevent yourself from getting ganked, which is easy to happen on battle and maybe the most common cause of death, avoid/run from disadvantageous fights, and look for match ups where you have a big advantage, say a 2 or 3 on 1. Also periodically check whats going on around you instead of what your doing at that moment, can get cav back-stabbed or flanked by other infantry. Staying alive is whats most important, risking your life to get the killing blow is stupid, you cant help your team or your score if your dead.
And in a bigger picture, often times at the start of a match people will split up into groups and go to differnt parts of the maps to fight, making the right choice on which group to go with can be the difference between being in the group that rolls the people they fight, or being in the group that gets rolled. Again in a melle fight dont matter how good you are if you find yourself surrounded and alone your going to get killed anyways. And know when to run from a fight when a battle is going badly, or atelast stay at a safe distance so you arent in danger of being quickly overtaken.
Alot of this is, decision making, is based on intelligence, if your not that bright you may never get good at it.