KISS, as in Keep It Short, Simple is an acronym that I learned a few years ago yet it’s one of the best way to describe how almost anything should work. I’ll talk a bit about how to have a secure server (or VPS, if you’re into that kind of thing) and avoid any nasty chinese h4x0rs trying to login using root as a username.
I’ll go about it in layers, from passive to active and from integrated to dedicated. I use Webmin/Virtualmin and Debian Jessie on my server, so some parts won’t apply to you if your configuration is different, but others will.