In Fly Fishing the term " match the hatch" comes up alot. With the immense diversity of insects that live and around Trout streams this can get confusing. Between Caddis,Mayflies,Stoneflies and Midges  there are alot of things to take into consideration. To make this easier to the begining Fly Angler a few easy steps can be taken to help to make catching fish a bit easier. First  before hopping in the stream and tying on what fly you think will work, look up in the sky  do you see bugs flying around or look at the river surface are there bugs hovering over the stream and last, shake a branch of a nearby tree or bush  and see what flies off.  Next try and catch one  see if its dark colored  light colored  does it have down wings  up wings  and get a general size of the insect. Look and see if trout are regularly rising then look to see what flies in your box look most like the insects that you see the most of  and you might just have a little more luck. Remember  Trout do not like to spend energy chasing food  they prefer an easy meal. learn the bugs  and you will have many happy days on stream.  Here are a couple of  good books  to help.  Trout Stream Insects by Dick Pobst.   Cripples and Spinners by Kelly Galloup.    Tight Lines and Hopefully Fish On!!