There is a good article on setting the hook in Shallow Water Angler. “Most of us work so hard on our fly-casting fundamentals that closing the deal once a fish takes the fly seems an afterthought. How many times have you heard a fellow fly fisher bemoan a botched hook-set after a perfect presentation or a hair-raising strike? It boils down to poor fundamentals—how you stand, where your rod-tip is, and what you do with your line hand.”
While this story is primarily aimed at saltwater fly-fishing anglers the sections devoted to striking with the rod-tip close to the water and pulling back with the line –hand is great advice for all fly-fishers in fresh or saltwater. I have been a strong advocate for this method of striking.
The one divergence that a fresh water angler may have with that recommended in the article is that the author recommends pointing the rod-tip at the fly, and this is good advice where current is not usually an issue. But in freshwater where currents can bend the line, the rod should be pointed in the direction the line is coming off the rod-tip. If the rod is not pointing in the direction of the line you run the real risk of just lifting slack line off the surface of the water and not setting the hook.