Different databases search different sources and types of information. Select a database by thinking about the subject area and type of information you'll need for your research.
Some databases contain articles about different subjects (for example, Academic Search Premier), and others are subject-specific (for example, Business Source Premier for Business topics and ERIC for Education topics).
Also, be sure you know the difference between the database name and the database provider (which is the brand or company) that hosts the database. For example, EBSCOhost is the name of the database provider that hosts Academic Search Premier but it also provides access to many other databases.