Re: Make all or most of the decisions to become the alpha
I watched a lot of Star Trek TNG. Picard was an alpha because he made the decisions and didn't hesitate. In fact, I remember one episode where he was explaining to one of his crewmembers that he makes decisions confidently, because if he didn't, then his crew wouldn't believe in or follow him.
Even though Riker was his first officer, I would consider him an alpha too based on his personality but beta professionally because there's an organization he was a part of and he had to follow orders. Worf also appeared more beta to me as did Data, even though he was smart.
I suppose it has to do with how a person comes off. At any rate, I believe being more alpha can be learned.