One of the best things about fishing in the summer is that you can often cast dry flies all day long. When working a stretch of river, you can alternate casting upstream to cover the head of a pool and casting downstream to propel your fly through deeper water or the tailout.
In this video Joe Rotter is from Red’s Fly Shop demonstrates the differences between an upstream presentation, where you must immediately start slack-breaking by stripping the line, and a downstream presentation, where you must do so add to loose to allow the fly to drift away from you. It’s a subtle concept, but one that will make all the difference in your ability to dead drift either way. I love the way he adds the idea of running a bit downstream to extend the drift.