another idea, since it seems you've decided on freshwater, is to check out the different types of FW
fish that are being sold. it can give you a starting point for your research becuase i know it can be confusing when trying to decide on what to research/what book to buy or rent from the library (because there are soooo many!). maybe check out liveaquaria.com and see what types of fish you might like to research. i like this site because they mention the types of perameters specific fish like, if they like to school or not, how big they will get, etc... and then go find a local fish store that you can trust. good luck and have fun with it!!!
ps- don't pay too much attention to the prices on liveaquaria, you might find the fish to be cheaper or more expensive at your LFS
... just use it as a reference to see what type of fish you might want to have