Well, most of the servers you see rise and fall either are the servers where they open, and everyone likes them, and they either get old and stale after a while or staff get's power hungry.
But to me, what a server needs to be successful in my eyes, is as little staff as possible. There is nothing worse than joining a server that has 15 different staff titles, and there are like 20 staff, and 3 owners and 10 admins. It's just bad for everyone. The staff also have to have respect towards the players, they must be polite, they must have experience, they must be 14 years or older, they mustn't pick favorites, and they mustn't give out items to players. Second, the server has to look good, plugin wise, and build wise. If I join the server and you have default everything on your plugins, that's going to show me you really don't give a shit about us you just want money. And if I join and you're still configuring permissions, then that let's me know you're either a little child that shouldn't own a server, or a person who can't pay for their own server monthly so they rush everything, which is horrible. The server construction must be great too, like I don't want to have 30 different plugins that do the same exact thing, or too many plugins that won't benefit us at all. Third, the building quality must be good on the server. Like if I join and you just have a wooden plank cube with a few colored signs and a shitty walk way outside of the cube as spawn, then you obviously want us to leave right away,
Take your time with your servers people if you want to be successful, never rush production.