Move. Cover water
I must have ADHD or something along those lines. I just can't fish the same piece of water for hours on end. It drives me bat-shit-crazy. I gotta cover water, fresh water, new water. I'm always looking for the "players". Fish that are actively feeding and willing to participate.
Observation of other anglers over the years has led me to notice many anglers fish the same piece of water for a lot longer than I would have. Not saying they are doing anything wrong, it can simply be a difference in fishing style or preference. However, what I do notice when I'm constantly covering new water, or my fishing buddies are moving around trying fresh water, fish are found more often than not.
Repetitive casting and angling in the same section of water can potentially alert the fish of your presence. Like other articles I've written about making your first cast your best cast (HERE), the less the fish is notified of you, the better.
Let me elaborate a little more on this subject. When covering a run, pool, or "fishy" slot I of course will fish the likely water water up close, but then I work through the water. Each cast and drift reaching a new section. If I felt there should have been a fish in a piece of water I will try another drift or two, but rarely would I exceed a handful of attempts. Onto the next section. Whether I was planning on working up or down, I move. Moving a few feet, moving a few yards, heck moving to a whole new run. I cover the water, and then go find another stretch.
On rivers like the Spokane we have low numbers of fish per mile. I find that covering water quickly and efficiently affords me more shots at fish. Driving along the NF Coeur d'Alene River recently both Mike and I have noticed anglers in the same run or pool for hours on end. HOURS. Maybe they're catching a bunch of fish in the same spot over and over again? I'm not sure. I know after one or two passes through the run or pool it's time for me to move on, as long as your presentation and fly choice were good.
Similar thoughts could be exercised when fishing steelhead rivers. Since you are not fishing to high numbers of fish per mile, cover water. Covering water gives you more shots. More new shots can lead to more fish. Unless you can physically see the fish in the run, you really don't know if there is a fish lying there.
So next time you find yourself fishless on a stretch of water get the concrete out of the those wading boots and cover the water. You might just be pleasantly surprised there was fish nearby that you had not encountered yet.