Look Before You Leap
When you first start sight-fishing, your first step should be to keep your eyes peeled for everything. When you do catch a glimpse of a fish, pay attention to what you see. Try to tattoo that image in your brain so you know what to look for the next time. The vision of an angler is somewhat like a muscle, and practicing is how your eyes become "dialed in." The more you sight-fish, the stronger it gets. Maybe at first you will be able to see a coloration or a shape that you know is a fish. But until your eyes are trained a bit, you may not be able to determine what species it is or, more importantly, which end of the shape or coloration is the head and which end is the tail. You'll be surprised at how much better your vision will become after a little practice. It's not so much that your eyesight improves but that, after time, your eyes simply know what to look for.