The boys over on Midcurrent have a good article on hooking fish on tiny flies. By far the best take away is the idea to strike downstream. Striking direction is honestly something that I’ve never put much thought into. However I think it could really help hook some more fish. Good advice, quote below.
But a better approach is to try to plan the response. Maybe the best general rule is to strike downstream whenever possible. With the fish facing into the current, striking on a downstream angle will tend to pull the fly into the corner of the fish’s mouth, affording the angler a secure hookup. When you’re making a classic up-and-across presentation, the instinctive response of yanking back or up usually works okay. But if the fish is only slightly upstream, or is across or slightly downstream, striking on a steeper downstream angle with the rod tip will produce better results. Downstream presentations always create hooking problems because the natural striking response tends to pull the fly away from the fish, back out of its mouth.
I also appreciated the humor in the idea that the when presenting downstream, you are out of luck. Just hope the fish hammers it and hooks itseslf! Good stuff.