One way to get started in researching a playwright, staging, social and historical context, etc., is to find relevant handbooks and companion volumes, such as the Cambridge Companions, the Oxford Handbooks, and the Blackwell Companion series.
Essays in these volumes provide overviews of topics within the larger subject area, and are by authoratative scholars. In addition to providing you with background and vocabulary for further inquiry, the bibliographies included are rich resources for further reading.
Here are some examples:
The Oxford Handbook of Early Modern Theatre
The Cambridge Companion to Women's Writing in Britain, 1660-1789
The Cambridge Companion to English Renaissance Drama
Companion to Renaissance Drama (Blackwell)