It is important to select the correct database for your topic. If you're not quite sure how specific you want your topic to be, then using one of the more general databases might help you to narrow your search.
Once you know what your topic is, choose a database that best fits your topic. Example, if you are doing a report on Wind Energy, there are several databases you could use. Junior Edition - K12, Science in Context, Global Issues in Context, Expanded Academic ASAP, and Opposing Viewpoints in Context. Even with just these four databases, the amount of information available is enormous.
It all depends on what point of view you are researching Wind Energy. Is it from the point of view of science? Social impact on a community? Business? Remember to keep your point of view in mind when selection resources of any kind, but especially databases.