In another group's microscope playtest report, the writer linked to The Improv Wiki. For people new to games like microscope, which don't provide many (or any!) explicit scene-resolution mechanics and which encourage taking the author stance, the experience and advice of improv theatre actors is priceless.
In our game of microscope I found myself struggling to set up scenes that could be interesting when it was my turn to do so. When I was entering a scene someone else had set up, I felt a distinct lack of threads I could pull on or buttons I could push to make the scene go. These are just the sorts of things that improv actors practice all the time! After reading just the two articles on Reincorporation and Disrupting a Routine, it was obvious how much a wiki full of tips for effective improv acting could help me get the hang of playing microscope.