Here are a couple simple rules for portrait photography:
1. Don't shoot up the nose!
Sure isn't flattering ;) You may think: "It's a cool angle...why not take it?"
Portrait photography isn't about cool angles. It is about making your subject look good! It is important to portray them in a flattering way.
So find a different angle :)
2. Women turn heads toward the higher shoulder. Men toward the lower.
I'll use myself as an example:
The above pose looks more masculine than the one below. In the photo above, see how my head is tilted toward the lower shoulder? In the below photo, I'm tilting my head toward the higher shoulder. The second pose is much more flattering to a girl than the first.
I don't have an example of a male leaning both ways, but I think you get the idea!