Using polarities to help develop charters
When you charter your tests, see what happens when you use different test polarities to develop your test charters. For each test idea, run it past some of the different polarities. How would your testing change if you focused on individual tests vs. general lab procedures; or coverage vs. oracles; etc… I find that doing this helps me generate far more test ideas than I otherwise would. While they aren't always high priority, the ideas come. That's important for overproduction and abandonment.