I just started playing orcs after playing reign of chaos's campain. I find in most team games, shaman with bloodlust and alot of units is a powerful combo, so is pure tauren with pulverize and shaman to back them up, or the wind raiders are pretty good to go in just about any game, the war drum guys are really good, get a few of them and use them, last game i was in a team game with 2 of them and i devoured 2 mountain giants
. and i had a bunch of grunts and wind raiders, raiders are really good if your going pure ground and dont have alot of air control, using ensnare is like web, drops air creatures to the ground, it also works on any unit(including heroes), so if there running away and you want them dead, ensnare them. The witch doctors are really good imo as well, harder to use but still good. I find all 4 of the heroes are really good so cant help you out there. Like i said I have only recently started playing them, and they seem to be an easy race to be decent with. Good luck, and i hope that helped, and anyone else got something to throw in at my advice or if you think something different let me know.