Fly fisherman are well aware of the match the hatch fishing technique. Use a fly that matches what insect is currently hatching and you will increase your chances of catching a fish. This technique works for other types of fishing also, not just fly fishing.
The problem I had with this concept was understanding why matching the hatch worked. In my mind I thought that if all the fish in the lake or river where feeding on frogs then a nice juicy night crawler or minnow would induce an instant strike because I was offering the fish something different. Then the concept was explained with an analogy that I could understand.
Imagine going to a steak house and smelling the wonderful aroma of a steak grilling. The smell is everywhere in the steak house and just the smell alone makes your mouth water. Now the waiter comes to your table and you order the best Porterhouse steak in the place. You wait in anticipation for that wonderful juicy steak and in about 20 minuted the server comes over to the table with your order, only they set a plate of chicken strips in front of you. What would be your reaction?
Remember this analogy the next time you go fishing and try to use or imitate whatever the fish are currently feeding on. If they want steak, give them steak, not chicken.