I had the idea of creating an unofficial faction.
I'm probably missing it but I can't find a post about the rules creating one.
Can anyone help me out?
There is not a set of set rules for unofficial factions. Generally though, it's wise to follow a similar format as Officials though (One ID for faction for instance). Also is to study up on the lore/background of other factions with the same ID. Just for reference. Lastly, don't powergame. It's not wise to make a faction that discredits others work. Say, creating a Outcast group that claims that they are responsible for Gallia entering Sirius space, or something else absurd. Being creative is good, but making your faction OP and inRP control other groups, or is responsible for other groups is not.
Hope that helps somewhat! Feel free to ask others too, as i'm sure there are caveats to the above, or more people could suggest.
EDIT: Great like that Snak3 provided. Forgot about that one.
Most of the "rules", or accepted customs regarding a new faction, are learned through experience in playing in existing factions/groups. Having both the knowledge and the experience, as well the good council of older members, is a recipe for success.
You can do two ways.
One: Write everything you have about that faction of yours, store it for a few months, and play in other groups, getting the feel of the game and community. After you get comfortable with the gameplay, review the writings you had about the faction, make alterations and present the concept. Iron out the flaws with the advise of the others, and make your way to set a your mark in history.
Two: Skip the whole experience months mentioned before, write everything you have on the faction, and present it right away. Deal with the troubles that may arise, and research about the proper forms to present your faction and getting people to play with you.
Always best to follow the first way. I'm just starting on the faction making things myself.