How do I quarantine to Vhost and no root access, and other security?

[Jun27]

What measures should I take to secure the server and how would I do them? I want to make sure most importantly, that if something attacks my site it will be quarantined to the domain and not have root access. I'm using a dedicated CentOS server. I want basically the same security I would have running under a shared server.

Please break it down in detail because I am still learning, this is the first time I have used CentOs and I have only used Linux in a shared environment before.