Going to toss in my advice as a long-term group leader~ (19 months of activity)
1 in 10 members will go inactive. That's just how it goes, in my experience. You'll get 30 people over the course of a month if recruiting is good and you might end up with 5/7 actives that stick around, IF you put in the effort in keeping them. Of course those numbers fluctuate depending on the time you spend recruiting and what kind of group you have, and FH's own activity at the time. But uh- here are my tips!
1- Have a decent website or a place for information, and make sure that this website is ORGANZIED and the font and color scheme is EASY to read! If I join an RP and find the website or place of information is hideous and all over the place, then I quit. This can simply be a group bio- but if you're aiming long-term you'll want something more.
2- Have a good staff team and base members. This can be hard, but it's even harder to start an rp all on your lonesome. Get some friends to join, friends you know are active and responsible, and have them make high ranked or interesting characters. These friends are your staff and even if you as a leader cannot be on all the time, they should be able to step in and start rp when you're not. KEEP IN MIND that the LEADER tag will ALWAYS make a bigger impact on members then a deputy, beta, etc.
3- Roleplay immediately after recruiting. Don't recruit until people are logging off- get one, two people, then go back and rp with them. People are far less likely to stay if they don't rp their first day. My technique as a WC leader was to immediately rp putting patrols together, lead by people already in the rp who knew the territory/ways around. They'd help newbies get into the swing of things, and then your members are FORCED to rp together- nobody can sit in the corner and whine that they were ignored or that their character is 'too shy' to approach others.
4- Make recruiting a group-wide thing. Encourage members to send out creative and funny ads. Get a line going, chat and be friendly to other groups. NEVER, EVER pick a fight or act salty towards another group in fluorite. They're not 'hogging' or 'stealing' members- people pick which group to join and accusing other groups of this is eXTREMELY insulting to people who joined them, at least IMHO. Use movie clips and local
5- Have a main plot in the works from the get-go. You need something, sandbox rps just dont work on FH 90% of the time. Try to avoid cliche tropes and make it something members can get inVOLVED IN. Another example from a WC rp: Plot was DF bitter cats trying to wipe out the clans. We had members apply for 'plot roles' that were a secret! We made sure they knew they might be playing bad or good guys, and asked tons of questions about their characters, and then picked the ones that best fit DF trainees. This way the entire plot was run by members and one, ONE staff leader.
6- Like I cannot stress the above enough make sure your main plot revolves around more then just one leader.
7- Like mentioned above, enforce your rules- and have good rules, please. Don't be vague, be specific. Also keep in mind that as a leader you need to be willing to take advice, but also know when advice is bad. People will whine that you don't listen to your community but if the community is arguing to allow sparkles in a completely realistic rp, you shouldn't have to bow to them.
8- Have random events all the time. Seriously. Hunting patrol? Have someone make an elk for the wolves to battle, then have a pair of hawks or a flock of crows try to steal the prey. Heck, let people apply for 'plot' crow roles they can play when leaders give them permission. Have bears attack patrols, have a rock slide bury half of camp. Let people apply for random injuries and then deal them out during patrols when nobody suspects a thing. Make a sweet character that everyone loves and then kill them brutally. (someone did that to me i stg I still hurt rip), Get people involved. IMHO, it's best to not tell people these things are happening unless it's a MAJOR event like a group v group raid. Border attacks, minor battles, and all these events are best left as surprises.
9- As mentioned above, you want surprises. You want people logging on wondering what will happen next. Don't tell everyone when something scary or dramatic is going to happen- I speak from experience when I say there WILL be a group of 3 people who ONLY show up for plot events. Only plots. They will never come on any other time and if you don't let them go to the events, and pick active members instead, they'll start spreading rumors- that's just how it is.
10- Favor new and active members. If you have a choice between a new member and an old, inactive member to put on patrol, pick the new one. In my experience people do better when inactivity is clearly not rewarded.
11- Do not recycle staff into high rank spots. Keep a rank until you find a normal member good enough to replace you, then promote them and die eventually whenever. Keep in mind that this person needs to be trustworthy ooc and IC.
12- Have an ooc presence. Enthusiastically greet people when they come online. Ask them about their day, compliment their character, ask to rp and hold a conversation. Just say things. Be a visible presence. if the leader is super active and rps a lot but doesn't chat and connect with members, they won't stay.
13- COMMUNICATE WITH STAFF. make a skype and share everything. screenshot impulsively and save it. You'll be grateful. Never answer a member unless the staff are in agreement or big boss has approved, never publicly slander your staff/leaders, it makes you and the rp look bad. never publicly slander the plot, NEVER publicly slander your rpers. In fact, don't gripe about your rp or the people in your rp ever unless in complete confidential private. If people aren't being active, pick up your plot and recruiting game. Don't make announcements about activity, inactive people don't care and it makes you look inactive to new members.
EDITED- A FEW MORE
Keep in mind that no matter how nice you are, when you have an active group with hopefully 20+ plus rpers coming on nightly, (plus the semi-actives), you can NEVER please everyone. You can try, but unfortunately when you have so many people, and when many of them are younger users, it's impossible to make everyone happy all the time. Someone will get upset over a decision and leave, especially if you enforce the rules. Someone will get upset over a name change or a color change- and that's okay, don't make exceptions for those that throw a tantrum! Just try to stay calm and keep your group calm and stuff!
Whatever your plot is, as long as you avoid cliches and directly copying from other rps, you should be fine. There have been so many FH roleplays you'll be hardpressed to find one that isn't very similar to whatever plot you go with- that's fine, One (bittersweet) aspect about FH is that so few mapped/large-grouped roleplays survive to play out a grand plot to the end. If you keep people entertained and let them be apart of it, they'll be fine with something even semi-generic. A well-plotted WC rp with the original four clans can still be active and fun, even if lots of others try to do it all the time! Same goes for wolf packs, lions, etc. Just you being you and involving members can make it way more 'fun' and 'unique' then another RP that tried the exact same plot and died in a week.