1. Identify your era or historical period.
2. Gather background information to identify key events, locations, people, etc. (try the Oxford Reference Online, Wikipedia--don't cite this!, Encyclopaedia of the Hellenic World, Google, and other sources that give overviews).
3. Search for those specific events, locations, and/or people in an online collection (try the World Digital Library, EKU's online search, Google Scholar, or an article database).
*Evaluate your sources!
When searching for primary sources, consider what type of document/item will help illustrate aspects of the time period you are researching. (Diaries, letters, newspaper articles, government documents, photographs, art, etc.)