Great advice from BigJim--
As far as flies to try when trout aren't rising, this time of year a small terrestrial like an Ant or Beetle pattern would be a good choice for a dry fly if you have long slow stretches with a lot of vegetation along the banks-- if you see or hear a lot of hoppers buzzing around as you walk to the stream, they could be a good bet also.
You could also try a subsurface pattern if you're not getting any action. Nymphs tend to be a bit harder to fish, but you could swing a wet fly like a soft hackle by casting down and slightly across stream and let it swing in the current below you-- it's a good way to cover a lot of water.
As far as where to find trout, "current seams" (where 2 different speeds of current meet) are a great place to find trout. Fish can hold easily on the side with slower current and watch for food to come by on the conveyor belt of faster current. It sounds like that trout you hooked might have been holding in the slower water and zipped out into faster current to whack your fly as it raced past. You'll often find seams shaped like a "V" below rocks or other structure that breaks swift current, at the head or tail out of pools, or at the edge of slack water and moving water in pocket water behind obstructions on fast water sections like riffles and rapids. Look for bubble lines-- they're a good indication of a seam.
Here's a good article from Midcurrent about reading a trout stream that might help identify good holding water and help eliminate water like shallow flats that are more likely to be barren especially in high summer temps.-- Reading the Water | MidCurrent