Experiment with color. For inexplicable reasons, gold works one day, silver the next. Dark colors, black or brown, often produce best under overcast skies. Use the smallest possible lures that will reach the desired depths. Generally, choose a heavier line to muscle the fish away from the heavy current.
Murky water helps conceal the line.
Try 8-pound test for starters. Go lighter if you're not getting the proper lure action or sink rate, or if the fish are small. When casting out to explore pockets behind boulders, quarter the delivery upstream, then swing the lure across current to achieve the desired depth and action just as it reaches the target area. There's an added serendipity to spin fishing these days. With the demise of the rainbow trout population from whirling disease, browns have assumed a much greater presence in most streams.