Yearly costs for a GoDaddy virtual dedicated server is ~$300. I have been using their Assisted Service Plan for $700, and I want to dump this service to save money.

I am a PHP/MySQL web developer and I want to take on the challenge of administering my own server.

I have Plesk installed on the server, and I imagine I will have command line access to the dedicated server.

What unknown challenges lie ahead for me? What are things to monitor to keep the site running efficiently? What should I be using to connect to the server? What tools are available to help me be more efficient?

Any advice would be helpful, thank you.