First, I have to say that "Duality" is superb! You definitely look good either way!
I agree with Lorileah, you appear to have that "bad boy" James Dean thing going for you so maybe warch some of his movies and see if the moves and manerisms fit you.
Basically, being a guy is about owning/occupying space, very territorial, and if it wasn't for the thin venier of civilization any situation that offered the least possibility that someone was "in your face" would be grounds for agression.
So be bold! And don't smile!
Really, that was a tricky one for me going the other way (MtF). Women catch each other's eye they smile a small smile at each other. Even if it is accidental eye contact with a total stranger across a crowded room. Women don't smile at strange men nor acknowledge them.
In boyworld it is pretty much the opposite. You can certainly look at women (that's even encouraged!) but you don't acknowledge them unless you are tryingto meet them (and maybe date them, or at least find out if you can take them to bed). Eye contact with other men is avoided unless they are your friends or family and even then eye contact is usually minimal. Watch two women having lunch together and then watch two guys.
But if you do happen to make eye contact with another dude, like walking down the street in the opposite direction or something, you nod without smiling.
Oh! One more thing! But you probably already know this one (as well as many of the others I've just written about). When you walk into the restroom you always go to the urinal farthest from any other guy. And definitely no eye contact nor conversation there! Even if you walked in with your friend and you two were discussing something when you hit the mens's room door.
An excellent presentation on men's room etiquette can be found
here (contains audio).
Enjoy the new world, Shark!
Hugs,
Persephone.