where.... what river? it makes a difference, but a midge pattern is what I would use, right now a grasshopper will kill all day on the right river, and any terrestrial ( ant, beattle, blah blah blah ) I always keep a black ant I tied to float in my box, when I see a fish that iis rising consistently,, I cast to him, this works a lot. you can also try a stimulater or any searching pattern, but in bright daylight I would go as small as possible. Its a pretty common mispercetion that most hatches come off at dawn or dusk, many stonefly and damselfly hatches happen in the time the sun starts heatin the water so you have to get your hatch matching skills down, in n.idaho and western montana many hatches come off all day, so time of day really plays no part in fly selection. If you are tryin to pop a fish but getting denied, and you are sure your match is good, you should ad a new tippet, and go as small as possible, most flies are tied about 2 or 3 times larger than they should be, remember, the slower the water, the smaller the fly. If you are really wanting to get into dry fly fishing I would recommend a 3-4 wt rod with a nice double taper line and the longest leader you can cast well, and size 16-18 flys, I find if I don't have trouble tying it on.... its too big.