There are apps that will go around and look for those pesky pref files. I use "Clean-App", it's shareware, but I know there are some freeware ones out there that might do the trick.
It's good to see that you're diving right in, and getting really involved with your Mac.
To save you some time waiting on responses, try looking here (http://guides.macrumors.com/Mac_Beginner's_Guide) first. It may just answer your question.