These four (1 handed) Bastards swords deal Earth, Fire, Water and Air damage. They are one handed so you can also equip a shield along with it. Now, I sharpened them fairly well and they do 100 something - 176 or so damage. Thing is, I have no idea how I can make this even better using skillpoints, since there's only Slash, piercing, crush, shadow and bone in the skill With Shield.

Does anyone know what I need to raise in order to get more damage/accuracy/death blow etc?

The Question isn't how
The Question is when
and the answer is now