multisite best-practice theory usage

I'm looking for some help with best-practices, and pointers to effective documentation to help me set up a multi-site install to help give student groups at the .edu I work at, a real effective web environment.

The messy way to do that is to just deploy a new drupal site any time someone wants a new student group website. But thats just asking for problems down the line with patching and management... I know how to do that, and, I know the minefield that presents when the many different student groups all want websites...