Two main areas are patterned in white knights (Maple Story mesos) are elemental attacks and defensive tactics. Their ability to use Fire, Ice, and Lightning charges makes them very strong against anything weak to those elements, although they deal less damage over time against enemies not weak to an element, out damaging the other two classes over time and providing steadier knock back. Additionally, they can freeze and stun mobs combined with Threaten; this provides them with a good balance of defense and offense that makes them the game's premier solo class.
For WKs, the only things set in stone about elements are that fire is good against ice, though the holy element will not be available until 4th, ice against fire, and holy against undead. For the rest, lightning is good against some fire monsters and some water monsters. White Knights in game (Maple mesos) continue to use Power Strike (260% damage) and Slash Blast (130% damage) as their main attacks. However, they may use these with an elemental charge.
This steady string of damage results in more Maplestory damage over time on a single target than Crusaders or Dragon Knights, as long as the monster is weak to fire or lightning. If not, Crusaders will deal more.