The beauty of fishing is just when you think you have figured it out, just when the conditions are perfect, the fish do the exact opposite to what you expect. This is what keeps fly anglers like myself going back to the river time and time again!
As a beginner, there are certain things you can do to shorten the odds in you favour.
1. When you get to the water, before your start fly fishing, spend a few minute looking around and observe.
2. If you see plenty of fish rising then they have their “eyes up” and are likely to be feeding on emerging or hatched flies floating on the surface. On a still water, look for a corner where the wind is blowing towards the bank and you will hopefully see lots of dead flies floating on the surface. There is a high chance that this is what the fish are rising at so you can match the appropriate fly from your box.
3. If you don’t see the rings of rising fish but instead see lots of tails or fins breaking the surface then the likelihood is they are feeding on nymphs or other water based food within the top few feet of water. Again you may be able to find out what they are feeding on from any hatching flies although it’s quite possible that although the nymphs or larvae are in the top layers of water they are not actually hatching. Some knowledge of the water as well as the time of year will help determine what may be hatching, I often revert to a black buzzer or small black spider in these situations with pretty good results.
4. If there is no movement on the top at all then there is one of two possibilities – either the fish are not feeding! (not good) or they are feeding in the mid layers or near the bottom. In these situations I normally start exploring the bottom with heavy flies and a sinking line if required. This is because there is plenty of food near the bottom such as blood worms and caddis which the trout may be feeding on.