Don't give all your friends staff ranks or anybody who joins. Nothing makes a new server fail more than having 7 Admins, 5 Mods, and 2 players, etc. Everybody who joins sees everybody is staff and asks for rank too then leaves when you say no. You're just killing yourself. I'm starting a new server. It's just me and a friend. We are Mods. No Admin ranks, no Owner ranks. The server I was staff for years ago had over 100 players on during afternoon peak times and we only had 6 staff members. There's no need giving every ranks for joining.
Give free diamonds on join. Really Factions is all about who has the most diamonds. Why would somebody leave a server they've been playing on for yours when they have to start with nothing?
Have something they can work for. Enable an economy system with a quicksell shop they can sell mining blocks, farm items, mob drops, etc. Make a shop like Sneakyy said. Sell permissions like enderchest anywhere, extra kits, etc. Maybe have a currency that is only earned from voting and sell custom enchants, factions powerboosts, etc.
And have everything complete before you start advertising. I have a friend who's had a server up for over a year yet he hasn't even finished setting up plugins or permissions. Yet he bumps his forum post everyday and asks why he never has more than 2-3 players online. I'd say making a server public that isn't complete is about as stupid has having a server with 10 staff members and no players.
These can apply for all servers. Just have it complete and looking professional. Give players something to work for to continue playing. It's not 2010-2012 anymore where you just start a server and advertise. People want some way to buy perks, nicknames, etc. whether it be in game economy or donations. Give free diamonds on join, like 20. Enough to make kids join but not enough to start with full diamond armor and tools. Before you know it, you'll have a bunch of kids asking for more perks and plugins to add. Listen to what they want. "I'll even donate for it!".
