Multiplayer Games - How do they get popular

Hello Gurus,

2 days ago i launched my first game which is a “Fun Run” inspired game called Fun Fight Multiplayer.
I already got 30+ downloads, but whenever someone downloads and plays, because there is no other players online, they leave the game.

I was wondering how multiplayer games get popular so that they have atleast a dozen players online at any given time?

As i mentioned, it is my first game and i have no idea what should i do?