First wade out to where fish typically hold. Firmly grasp a small hand seine downstream of your feet on the creekbottom and turn over a dozen rocks or so. You’re not working a backhoe, just disturbing the bed a bit. Bring up the net and slip on the reading glasses. Also check the surface flow in the current below if fish are actively feeding around you. You should pick up hatching insects, as well as any terrestrials that have the fish turned on.