The FIFA scene is growing every day and is currently very big... just give it a go for the love of god!
The set of rules are simple...
*online league game type, 6 mins, any teams*
*if player disconnects, play again with same score with remaining time*
*all players must screenshot score at end of the game*
done... that's all it requires.
As for the community... half the people on cadred play FIFA on PC... I was never expecting to get over 10 or so people on here who would be interested for the reason that the UNGL forums aren't as populated as cadred forums or other esports forums.
You can search cadders, tek9, etc etc and you'll find threads lots of threads. You could even say that FIFA unites players from different fps/esport games together...
Somebody once did a one night fifa 12 cup for their org once and advertised it on cadred, it was full before the thread was deleted - and that's an achievement, believe me!
With regards to preparation, just give it a shot, I'm sure myself, the other people on here and a whole bunch of other people within the css scene and other esports scenes are willing to help.
UNGL will barely require any admins, you will get a new influx of players = win win :D