All of the hatch charts previously posted can be found at the following link and are produced by Mr. Hugh Hartsell.
Regarding the similarities of the South Holston tailwater to the Holston tailwater below Cherokee, there is very little other than the name. The South Holston has phenomenal sulfur, blackfly, BWO, and midge hatches. The Holston is known as more of a caddis tailwater with somes midges and BWO's thrown in there. The hatch chart given below will not benefit you very much below Cherokee dam.
If you are going to fish the Holston, have some caddis larvae and pupae in #16 & 18, elk hair caddis (tan, black, & olive) in 16 &18, zebra midges as mentioned by somebody previously, and some BHPT's in 16 thru 20, and you should be covered.
One common mistake by beginning flyfisherman is using flies that are too large and are typically carried by the big box stores. Using a #12 BHPT will most likely get you nowhere on the holston. Same as if you were using a #12 elk hair caddis. Sure is easy to see, but does a poor job of imitating the size of the most abundant food source.
Secondly, get yourself some 9' 5x leaders. Also buy yourself some 6x fluorocarbon tippet material, it will make a significant difference as well.