This is a very broad subject. Regarding specific tasks you don't want running, I would need to know what you would want to disable in order to tell you if that would be a good idea.
You can look in your WHM at the system processes or a better place for a "live" view would be SSH by running "top" from the command prompt. When inside of top, press Shift M to sort by memory useage and Shift P to sort by CPU useage.
The PowerPanel can show you information about your running processes as well.
A List of Some Common SSH Commands:
https://www.powervps.com/support/ind...&root=16&id=21
A Guide to the PowerPanel:
https://www.powervps.com/support/ind...&root=22&id=85