[Phantasm]

I find that Boardroom & Curia gives a number of useful ideas. Mostly, I've found the Mission Statement portion and Notable Resources details highly relevant, as those give ideas on what the organization is for and capable of. You don't need to give hard and fast numbers for membership in an org unless it's very small; most orgs have room for the PCs to interact with only a handful of NPCs. You don't need to stat out the upper echelons of the org if the PCs are only going to be dealing with a businessman front; think of how the Shadows in Babylon 5 operated through a handful of human and Centauri agents.

Originally Posted by Fred Brackin

A good general text description. Stat blocks are fine for conveying numbers when I need those but needing to reverse engineer a stat block into a section of text myself is not welcome.

I second this idea. B&C gives at least a page of fluff text alongside the stat block in their example organizations, much the same way City Stats does. Personally, I'd work from the fluff text and build the stat block from that rather than the other way around.