I've started two guilds from scratch both of which are now established within the game with over 2million fans. The forum is a good place to start as black monks has pointed out . The best advice I can give you is put a guild message up in the description something along the lines of hi i'm Thomas looking to start a fresh new guild , advice and tactics will be shared when we get enough members mini tournaments will commence within the guild to improve the team. Also don't aim too high with who you're trying to get onboard if your a 50 rated team look for players in and around your rating obvs it's great if you can attract better or know of a friend who is higher calbre but start low and build . I think when I started my first guild I only had 30,000 fans myself now my main one has over 3.5 million times but be persistent send lots of invites everyday and when you've built your fanbase up more serious players will join you the bigger the fanbase the more better calibre you tend to attract. Also to get started make the guild open that way anyone can join then when you get a few loyal members close the guild and make it invite only and build on what you have because you will already have members this will then make it easier to attract players once you already have players in your guild but the hardest thing about starting guild is getting the first 5 members once you do it's really simple but myadvice would be make it open for anyone at first get a few names in once you happy you've got 10 good members to start a GC who will play close it and make the guild invite only and be selective over who comes in or what calibre comes in
best of luck