Covering Water Effectively
Many times on stream you'll find yourself prospecting or surveying by blind casting, dries, nymphs, or dry-dropper rigs to likely looking spots. Remember when you are doing this that often the feeding fish aren't always in the deepest and most likely looking spots but are closer to edges or in the shallower parts of riffles or tailouts of runs and pools.
I have a friend (who we'll call Herbert to protect, sorry to the Herberts out there) who almost always approaches likely looking runs and pools and immediately casts over all of the marginal and even good looking water to hit the prime spot. In so doing he invariably scares most of the fish in the run.
Occasionally he catches a few which only seems to reinforce his bad habit. When someone else does this we call it "Herberting" up the run. A better way to handle this is to fish to the less likely but closer water first then work your way up to the prime stuff.
Don't be sucked in and immediately boom a cast over all the other fish you could have caught. If you cover water effectively you'll have the chance to catch far more fish and you'll still get to eventually cast into that honey spot.