In order to do a successful search for your topic, you need to understand the basics. Think about the "who, what, why, when, and where" aspects of your topic.
For example, if you are researching Mona Hatoum, but have no idea who she is, where she's from, or what artwork she is known for, then gathering background will be helpful to develop good search keywords, and to develop a refined research question. After gathering background, you can ask a question like "How did Mona Hatoum's Palestinian identity shape her performance artworks in the 1980's?"
Use resources such as Oxford Art Online, the Heilbrunn Timeline of Art History, and Smarthistory to find background information.
Encyclopedia & Dictionaries
Timelines and Overviews