Recently i have been doing a bit of graphic design and putting together a visual style guide, and i came across this handy page: http://www.smashingmagazine.com/2010/12/14/what-font-should-i-use-five-principles-for-choosing-and-using-typefaces/
The author essentially goes through his Five guidelines for picking fonts, and working with them. Even better though his guidelines are couched and contextualised in a fashion concept, and so give a broader comparison.
Helpfully he also takes the reader through a selection narrative, so that everyone can see how their font selections work together.
However, there probably needs to be a 6th guideline added: Never use Comic-Sans. For the reasoning there see here: http://www.comicsanscriminal.com
Really recommend reading it if you are doing anything with graphic design, even if (or especially if) you are merely dabbling in it.