Each race has its own element via passive racial skill. You should element it toward that.
I'll list them here:
Dark Elf: Wind
Elf: Water
Orc: Fire
Dwarf: Earth
Kamael: Dark
Humans have no element, but I recommend holy since holy isn't used by any of the other races.
This is for PvP. For PvE not sure I believe mobs resist certain elements and you should avoid those elements. Someone should clarify soon.