I dont know if this is the best strategy, but ill give it a shot.
1 Blademaster 1 Tauren Chieftan
6 Shaman
6 Witch Doctors
and as many taurens as you want/wyvs depending on what ur enemy is. If your enemy is undead, stick to the taurens because if ur enemy goes gargs and u got wyvs its game over. If your enemy is a NE stick to the taurens since they can own the most popular.. DYRAD strategys.
And as for the other 2 races i awalys go wyvren against orcs/human seeming bloodlusted warded wyvrens when used rite can own those 2 air categorys. Good Luck!