If you have a choice, you should always pick a topic that interests you and one with which you are already somewhat familiar.
For Topic Ideas
Here's a general rule of thumb: If you find too much published information on your topic, you need to narrow it; if you find too little, you need to broaden it.
One way to narrow a topic is to find an interesting approach to it.
Consider ways to subdivide the topic: time period, person, location, technology, or event.
If you find little background information on your topic, broaden it by removing one or more of the elements that make up its subject.
Determine the Boundaries of the Project
Consider the following:
Identify the Main Concepts
As you read through background sources (see the next section), try to identify the main concepts associated with your topic. Make a list of the terms used to refer to these concepts. You can later search for words from this list in reference books, periodical databases, indexes, and other information sources. Keep in mind that these sources may not use the same terms to identify your topic that you would. When looking at citations in periodical databases you can see the headings, or terms, used to describe a certain article in the "subject heading" or "descriptor" field. Find other articles on the same topic by searching under these headings. The same applies to book catalogs.