To recapitulate, before going on to discuss in a more general way the matter of fishing the floating fly, it would seem that the chief points for the dry fly-caster to observe are somewhat as follows: To use a single floating fly generally selected as to size and color with regard to the natural ephemeridae common on the stream at the time; to cast the fly upstream, allowing it to come down after the manner of the natural insect, favoring the horizontal cast to insure, as far as may be, cocking the fly; to avoid immediately raising the point of the rod or stripping in line at the finish of the forward cast, but to hold the rod motionless until the fly is well started on its downstream course; finally, to avoid drag by casting a slack line.
In general, dry fly-fishing as done in America naturally divides into fishing the water and fishing the rise. The dry fly caster when fishing all the water should proceed much after the manner of the wet fly fisherman: the angler who has been accustomed to fish upstream with the wet fly need not alter his general methods in the least, save as regards floating the fly and avoiding drag. As a rule, it is best to follow or wade along the left bank, looking upstream, as this will give you an unobstructed right-handed horizontal cast.
As the dry fly man works upstream and the trout habitually lie facing the current, the careful and quiet angler seldom needs to cast a long line—provided, of course, he is casting practically straight up and actually stalking the fish from behind. But when casting diagonally up and across from either bank, in which manner it may happen that a great deal of the water may be most advantageously worked, the familiar fact that "keeping out of sight" is half the battle in trout-fishing must never be forgotten. This time-honored rule of the trout-fisherman is, it would seem, quite frequently neglected by even the most experienced anglers, its non-observance often constituting the "inexplicable" reason for failure when casting to a rising fish or when fishing a good pool.
It is always best to use the shortest line compatible with safety, constantly bearing in mind the well-known very acute vision of the trout. The chances of failing to hook a rising fish or of eventually losing a fish successfully fastened increase measurably with the length of line in use. Moreover, with a short line it is easier to prevent drag because there is less line upon the water. On windy days when the ordinarily smooth reaches are choppy, and always when fishing the swifter, broken runs, a thirty, even a twenty-five-foot cast is ample, if you are fishing nearly upstream and take pains to swing the rod low. On several occasions, having allowed my fly to float down very close to me in order to lift it from the water without wetting (if you lift your fly from the water when it is well away from you, the pull upon the submerged leader drags it under), I have had a rise less than five feet away.
But to successfully fish close-up, the angler's progress must be slow, careful, and quiet, and the rod must be kept down low. Overhead motion, more than anything else, alarms the fish. You have only to pass your hand over a can of fingerling trout fresh from the hatchery to verify this and to appreciate the instinctive alarm of trout at anything moving in the air above them. Avoid quick motions—in fact, dry fly fishing is a game which simply cannot be successfully played in a hurry.
Not infrequently the downstream wet fly fisherman covers several miles of water in a day's fishing—I know, because I have done it innumerable times myself, and I do not say that there is not much charm, good exercise, and generally a few fish to be found in this sort of fishing. But anything of the kind is strictly incompatible with properly fishing the dry fly. The wet fly man who takes up the dry fly method should understand at the outset that the cast-once-and-walk-a-mile sort of fly-fishing is simply out of the question. If you know your stream, select a moderate reach of evidently good dry fly water, and fish it leisurely, deliberately, and searchingly.
Keep an eye out for rising fish, and observe closely the natural insects, if any, about and on the water. Cover all the water thoroughly, floating your fly not once but several times over the best places. If the water is equally good from bank to bank, let each cast be not more than two feet to the right of the preceding one, beginning under your own bank (generally the left facing upstream) and working across the stream. Then move up slowly and proceed to cover the unfished water above in a similar manner. Pools should be fished in the same way—covered thoroughly from foot to head. The matter of the most likely places to look for trout has been discussed in a foregoing chapter and need not be reconsidered here. The suggestions to follow on casting to a rising fish will also be found to have a general application in many ways to fishing the water.