Where are the fish?
Are the fish feeding?
What are the fish feeding on?
What type of fly is likely to be hatching?
Is or has the weather been hot or cold?
Are the fish likely to be close to the surface or feeding deep?
What is and what has been the direction of the prevailing wind?
Can any identifiable food sources be detected in any residual surface scum?
Are any birds sweeping low over the water and picking up hatching flies?
Are any fish jumping out of the water?
Are any fish rolling to feed at the surface?
Are there any “bow waves” due to fast swimming fish?
Is there any turbulence at the water’s surface due to fish movement?