You're likely already aware of the shouts people do in the various major cities in the game, it's hard to play without encountering them. That's one way.

Another is to make recruitment posts on websites. From what I know people usually make a recruitment post in the community forum dedicated to their server which is here in your case, a post in the Companies section or posts in this subreddit.

A word of advice; don't throw fc invites at players without even speaking to them. It's rude and intrusive.

As for running a fc, well I already touched on this in another thread, it's a lengthy post but might be worth a read.