Welcome to the forums
@Bethanne Rainbow !
Recruiting is hard! I see you've posted in the 'FS looking for Members' part of the forum for your world; that's the first piece of advice I'd have given you, lol, so you're ahead of me there. Some of the other things I'd do:
Ask members for help recruiting. It's not usually a good idea to have a bunch from one neighborhood (limits outside trading partners), but if you have members that are spread around the map, asking them to look for a neighbor who's an active trader and either not in an FS or in a mostly inactive one may get you a recruit or 2. Also ask members to check out other players near them in rank that may be looking for an FS. You can have them just send suggested recruit names to you or to you and the mages. Develop a standard recruiting message (what you're looking for, what you provide) for everyone to use (make it as easy as possible for them to help) and ask they send it as a message to anyone they want to invite in their neighborhood. Having them send the recruiting letter to anyone in their neighborhood makes it more likely the prospective recruit will recognize the name and at least respond even if they're not interested. You can just send the letter yourself to ones around them in rank that are not neighbors. That will get you noticed by players who have 10 invites from unknown FS's as well as setting out expectations.
Make sure those expectations are clearly listed on the FS overview page as well. I recommend making it so folks have to apply, not 'direct join'. You don't want to get a bunch of brand new players who do everything the game suggests including 'join a FS' in the first few days and then quit the game in a couple weeks and you just have to recruit a.g.a.i.n. It may be worthwhile to have on your overview page 'New applicants please send message to (whoever) stating (whatever: their boosts, expectations, what they bring to the FS, etc). This is a good indication of willingness to read the rules and follow directions when necessary (like in the middle of a Fellowship Adventure, lol!). You don't have to make 'strict' rules; you just have to make rules you're willing to enforce. IMO unenforced rules are just suggestions. Some example casual FS rules: Visit 3x's/week; minimum 2 star trades unless pre-arranged, score must change in 2 weeks(helps keep up with activity level). Notify (whoever, can be archmage, mage, or ambassador) if you'll be away from the game (no reason necessary) for (whatever period of time, 2 weeks, 3 weeks, etc) ElvenStats tracks score changes on a weekly basis and has a copy/paste report you (or a mage/ambassador) can send to the entire FS each week showing you actually care enough to track these things. Have a conversation with your mages to help decide on these rules. Any member who shows good communication skills and a knack for recruiting, make them an ambassador so they can issue invitations directly and accept applicants.
Check out FS's around your same FS rank. If you find one with just a few members (or just a few active members; use ElvenStats.com to check out activity), send a msg to them asking about interest in joining yours. Offering Mage status upon joining to the AM (or the member they choose) will help them feel they retain a voice in the direction of the FS.
I'm sure there's other things, but this should at least get you started. Good luck and don't get discouraged! It's hard for every FS I've ever talked to!