For most flytiers, the mayflies are the heart and soul of fly tying. In the mayfly gallery I present some of my patterns that seem to outperform other variants in the waters where I fly fish (Hedmark, Norway).
Even if these are my favorites, it is not certain that they will work as well in your waters. If the species hatch, they will work, but there might be slight variations in size and color of the fly. Fly tying and fly fishing is all about adaptation to your local waters.
Use these patterns as an inspiration to your tying. More detailed information on the patterns is found here