My suggested CS format. Feel free to modify it as long as the information is there.

-Faction Name:

-Faction Main Base of Operation:
(The location. Doesn't have to be a named city, can also be a general province's countryside.)

-Faction Goals: 
(What is to be achieved, your own victory conditions if you will... but remember that the world goes on around you.)

-Faction Composition:
(Not as much the number as the member's general religious, ethnic and cultural identities.)

-Initial Assets:
(Things that go out of the ordinary that your faction has managed to aquire, that can range from 'Significant amount of members' to more specific weapon assets or off-shore money as well as foreign support. All of this is veto'ed by me.)

-Methods of Operation:
(Do people have a lot of freedom of action? Is the leadership centralized? Right now, are people ordered to attack government forces or to evade them?)

-Faction History:
(Can be short or long, how your faction came to be? Did it already have run ins with the government? Etc.)

-Faction Leadership:
(The decision makers of your group. Take note that a lot of people will die and a satellite guided cruise missile can quickly decimate a leadership. Expect people to come and go from that list so if you have a 100% centralized leadership expect your orders to be followed to the letter, but with a certain vulnerability to decapitation strikes.)

-Faction Eyes: 
(To describe battles, you can hardly do so from the eyes of a leader as not to risk him. These people are small timer grunts, civilians sympathetic to the cause. You can be brief about these people and hey, maybe include a few grunts destined to be upgraded to leadership later.)

EDIT: Also, Say Anything, The Nexerus, since you two will have factions with at least some religious elements and ethnic ones, mind coming up with a religion each and if you feel like it, maybe an ethnicity?