Knowledge of terrain: If there exists a spot on the map which allows you to attack your enemy while not getting hit, why not use it? Use appropriate pots which appropriate for your HP/MP(Maple Story Mesos). Smaller pots usually have better meso/HP or MP ratio. Good MS players should seriously consider pots sold in New Leaf City, which for warriors and mages quickly become much more cost efficient than potions sold anywhere else.
Master HP increase Mastery as soon as possible. This will slow your training at first but it will increase your HP. Then by level(Maplestory powerleveling) 30, you will have about 1,500-1,600 HP. This applies to both normal warriors and HP warriors. You will lose about 500 HP If you do not decide to master it soon. Some say Final attack has the flaw of activating unexpectedly, sometimes at the wrong time. However, this helps you quite a lot in Maplestory. It speeds your training speed by a margin.