New broods of mice are due anytime now, which means predatory fish are going to be aware of their existence again. Because mice don’t magically fall into the middle of the water, typically. Cast so that the fly lands near the opposing bank and strip it back towards you — like as if the mouse is trying to make a break for the far bank. Give it a pause for a few seconds before starting to work the fly. Often times fish will hit it right as it smacks the surface or shortly thereafter.