Right now, according to the prestige helpfile, gaining prestige as a "commoner" seems to purely revolve around money - how much we tithe, how much we pay in taxes, how much we pay to people or NPCs. But I think it would make sense for there to be other factors as well such as:
- Does this person hold a position as a GL?
- How many people politically support (or subvert) this character?
- How many people politically supporting (or subverting) this character are people of note? (IE. Nobles or GLs, etc).