I'd heal.
Dark-Knight Essay, ammendments+ more tips
Yeah I would have to agree about the essays.
A Dk, like any hybrid melee should take full advantage of the wands and scrolls.
Like any class always have two forms of protecion (the spell you have and a consumable for the other align)
Dual wield against casters.
Two handed against other hybrids.
shields against dedicated melee's
Master ANY spell you even THINK you might use in combat (mastery means no loss of concentration unless your have been disrupted, and the durtion of some spells increases as well as the severity of their effects)
Master your heal
master your defences/weapons/combat skills
learn what races you should trip and which you should bash(remember size is important!)
Carry mundane (physical) and magical damage weapons if you can.
Learn HERBS, Learn CONSUMABLES, not knowing consumables and not being prepared is one of the largest contributors to power gaps between vet's and newer players.
The biggest thing to contribute to PK with ANY class is to make sure you retain the knowledge you gain from playing any other class. If you know that your enemy doesnt know axes, USE THEM. DK's can use every single weapon, this is more of an avantage than most think.
That's what she said!
Lol why are you casting armor with 4 hp!
Better than druid gate with 600 
Better than druid gate with 600
Sigh, dont make me roll another to prove you wrong.