I think Alpha is confidence, doing what you want without fear of embarrasment, ridicule, or attack on others, going for what you want, not giving in to others, going for yourself, having things your way, basically not yeilding to others when it takes from you.
I was at the bar with this girl, it was crowded, and we were standing at a table, and she was telling me things like: Don't move for other people. Don't move for girls, if they want to bump into you, let them. This because we were standing there, at a table conversating. I would think this as being an example of Alpha. A beta would move around, try to get out of everyone's way, etc even when standing at a table. This is an example of just how hard it is to fake confidence, because if at the very core, you're beta, not confident, you will be uncovered, and you will look even worse, because you are trying to pretend. But if you try to improve confidence, everything else will come. Even small things like moving for people at a table will reveal just what your mindset really is, and it will contradict the image you are trying to put off. You can't fake confidence, plain and simple, you have to be confident, you have to go for yourself, put yourself first, in a way.