My teacher recommended we know the synopsis and themes of 5 Shakespeare Tragedies and Comedies, and possibly a few Histories. I have made a folder with each play, brief summaries, themes, then an extract of a monologue (from shakespeare-monologues.com, best thing ever!) annotated. I know this is a bit much, but it is great to have to refer to and at least practice with.
Also, I have tried to do this with modern, Victorian and female written plays as well - so I am not limited to just Shakespeare.