How much time do you need to prepare for lessons? I have found that with experience it takes me less and less (still not true of my teacher training exploits though!). Here is a very useful article from a college professor James M.Lang which doesn’t only speak about the necessity to reduce planning time, but also suggests several low-prep activities that can be adapted to an ELT classroom. My favourite at the moment is ‘the connection question’, but there are others to try: annotation worksheets, writing warm-ups and polling.
Love those little efficiency tweaks, and you?