Adams
Biot BWO
CdC Para Emerger
CdC Blue Dun
Grey Wulff
LE CdC May
LE CdC USD Paradun
LE Paraloop BWO
LE ST Biot Dun
LE Vulgata
LE Rocken
LE Were Wulff
The may flies are common in a large part of the world. In nothern Europe there are more sedge flies but they are still common.
My approach is to make either a good profile - against the sky or as a pattern on the surface - or a good impression for the fisherman. After all, he's the one that choose the fly ;D
Of course I also tie the standard classical patterns, but I am not always sure what they imagine...