PsychINFO A huge index. No literature search is complete without consulting it. Check out the PsycINFO website for more information about the database and how to use it. Usage instructions are also posted by the student computer in the library. You can't get there if you don't know where you're going.
Searches usually go from the general to the specific.
You might not actually do it that way, but you should be aware of it. If you are doing a very thorough search, look at all the different media available to you. Journal articles usually cover a small idea in a concise manner. Books may cover the basics that articles omit, but they also have the space to go into greater depth. Dissertations are usually narrow but thorough.