How do I... "level up?"

I have no idea. You’ll have to wait for Deathdrop, I need to ask him for a level up.

Quote from the forum rules:

"Do not pester moderators for rank points, they will only be given out once they feel a member has earned them."

Good performances in RPGs & sparring fights (no matter if you loose or win, the quality of your posts counts) and a overall good conduct are criteria for earning rank points.
Asking for them on the other hand isn't very beneficial for earning points, nor making double posts.