Your Toolbox of Resources
The information you are looking for will dictate the type of resource you choose. If you want a broad overview of a topic or want to collect background information, you can begin with Google or with the Cornell Libraries' "search everything" interface. Keep your search strategy broad.
If you already have a good understanding of your topic, then you will want to search specific databases in order to locate research articles or browse specific journals. Search strategies in these resources will be more complex and include synonyms or subject terms to focus results.