In my experience, immediate conditions affect fish most. Large scale catch-all's miss the important smaller scale stuff.
We all gravitate toward, look for, the easy and simple way out ... reminds me of the bubble headed girl selling some wonder health elixir at a local fair I met. She finished her perky spiel with a vacuous "It's simple! You know, nature's really simple when you get down to it", finishing with a cute, and emphatic, little shoulder twist. I had been politely half listening but I think my jaw dropped when she said that, and I could only respond, "No. No. It's not. It's very very very very ...complex."
Does this mean that all measures taken of natural phenomenon are useless? No. The devil is in the details and that's where the complexity begins to show. But some measures are more useful than others –notably the stuff you said you weren’t asking about: “conditions”. Understanding them -combining knowledge and personal experience- ARE the shortcuts. In no time in history are there more "shortcuts" available than now. They won't include running your finger down a magic table, or having your phone beep, and tell you it's time to cast.
Not meaning to sound short, but I guess I've jumped to the middle ground between Roger's kind and harsh responses.