I've suggested to make daily events (or every 2-3 days) where we needed atleast 8-10 players to attend the event + 2-3 admins online. Rewards would be included also, so if we attract atleast 5 players to join our server while we're doing the event, then we would have around 15 players which is a success to me.
The biggest issue in our community is definitely age. Last time when the server had a respective amount of players online was like around 2014/15 where we all were just 16-17 years old and nobody gave a fuck about anything (except Tamer, he was old as fuck at any moment, born with a mentality of a 50year old divorced man), so keep that in mind. It's gonna be hard to go IG everyday, but not impossible.
Feel free to create a topic to organize meetings in game, that could be something for start.