We got all our people by posting on Aionsource and spamming our recruit thread 40 times a day to keep it on top. Now we have 73 people in guild with 20-30 of them on at any given time. "Advertising" on fan-sites is a good way to go... the best way imo is to group with people not in guilds with fellow guildies. Make it a guild event day and go to "pug hot spots" and grab people not in guilds and people in guilds a like. Build your rep and this way you can test drive potential recruits out and they can get to know you.
One thing I did in L2 sometimes was play an alt in lowbie zones. Sometimes there are new players and taking a few mins. while leveling your alt to teach them about the game you can find great new guildies. Just remeber one rule...anything you give to a stranger is gone forever...never loan NOT'IN! lol