Heya! While your criteria is quite broad, it always helps to narrow down what you’re into.
I recommend checking out this thread: WrA Information & Directories - #35 by Nevelis-wyrmrest-accord
Get your feet wet and maybe walk around Orgrimmar to see if anyone catches your eye! Military guilds are a dime a dozen, so you may need to do a bit of sifting to find something you like.