There are many factors that affect the success of your bass fishing. One of the most important factors is the sink rate of your fly. If your fly sinks too quickly, the fish will see it as a red flag and will most likely refuse it. This is especially true of warm-water species like largemouth bass.
Frog flies are a great choice for bass fishing, and more have been coming out recently. The Umpqua Swimmer is a great example of a frog fly because it is a surface/diverter combo that is highly effective at drawing the attention of predator fish.
Another fly that works well for catching bass is the Parachute Hopper. This is an excellent choice for cold-water bass. The size of the fly should match the size of the local crayfish, which will attract largemouth bass. You should fish the fly with a slow, even strip and bounce it along the bottom.
Woolly Buggers are another popular choice for bass fishing. These are small, soft flies tied with a hinged tail, which resembles a distressed baitfish. The bright, ultra-flash holographic eyes and body make this fly stand out from the crowd. The woolly Bugger comes in many sizes and imitates a crawling crayfish, stonefly, or even a dead drifted bugger.
The Worm Slider is another great choice for fishing with a fly rod. This fly gives the fish enough time to chip away at the fly until it is eaten. It also swims subsurface, making it a good choice for deeper water fishing.