Late summer is hopper time. Here are a few things to remember for great grasshopper fishing.
Look for streams running through meadows. There are usually very few grasshoppers in forested areas but in the late summer bugs abound in grassy meadows.
Toss your hoppers as close to banks as possible, especially those that are undercut by the current. I've watched several times as people cast at banks and thought they were drifting their flies close enough but when they got the fly right against the bank the fish could see it and gulped it. Don't worry if you hit the grassy edge of the stream as you try to get the fly snug to the bank, simply twitch the fly into water. What presentation could be more natural?
Also, see if you can find the natural grasshoppers along the stream and match them in size and color. You don't need to be exact with your hopper imitations but it doesn't hurt to be close.
Fish breezy afternoons. The casting may be more difficult but this is when the fish are used to seeing bugs that mistakenly fall into the water.