The most important piece of advice I would offer to an aspiring faction leader would be to join an established faction first (either official or unofficial), in order to gain an understanding of what's required to make it work first-hand, and also to understand what non-leader players have to go through. This is particularly important for those new to Disco in general, so they can become familiar with in-game mechanics, forum etiquette, and gain a broad understanding of how the community operates.
The core idea that I tried to keep in mind during my days as an Official Faction leader was "What can I do to offer the members an entertaining experience?" There is no faction without players, so it's important that logging on to the server is a positive experience. If that's too broad a question to answer, just focus on making their lives uncomplicated so they can focus on playing how they like (within the bounds of your faction's M.O., of course).
