Obviously you have to do the Hari Kari, steepest black in Austria
Red 7 is a favourite of everyone I know who has been to Mayrhofen
I like the runs over at Eggalm, fast reds
The long run down under the Katzenmoos chair is great too
Red 16 is the difficult one, known as The Ridge, and its carnage at 3.30pm
Also thoroughly recommend the long Ahorn Abfahrt if snow is good down to the village, real lthigh burner and some steep bits to attack but watch out for the ice!!!
Some nice runs over in Zell as well, especially going over the back to Gerlos
has better snow than anywhere in the region, get a bus up there early doors, and hear right to the top for the best runs.