"...research is not just finding something that already exists, but an endless...process of discovery that creates knowledge...To 'research' is to encircle, and the object of that encircling is not to find but to define." - Reed Wilson
When you start a research project, you're entering into a conversation that, in many cases, has been going on for a long time. Other people have been thinking and writing about your topic, and your job is to listen to what they've said, and then to contribute something interesting back to the conversation.
This video might help you understand how this conversation works.
The best way to find out what's going on in a research conversation is to look at citations. Citations and reference lists show you who's talking to whom.
When you find an article that is helpful for your topic, look at the reference list at the end of the article. This will tell you all of the previous "speakers" in the conversation the author is responding to.
In some databases, you'll also be able to see which other authors have cited the article you're looking at: who has responded to the author in the conversation. Look for links that say "Cited by."
The "cited by" links are on the right side of the article in Sociological Abstracts.
Google Scholar is a great place to find out who has cited a particular article. Under each article is a link that says "Cited by" and shows the number of articles that have cited the article you're looking at. Clicking that link will bring up all the citing articles.
A big part of an annotated bibliography involves not just reading your sources, but evaluating them to determine how credible the author is, how well the research was conducted, and how relevant the source is to your particular research question.
(It is important to note that databases also have inherent bias toward Caucasian, male authors, so be aware of this when looking at search results.)