That's a big question. Maybe I can't answer it. All women are different. But generally speaking, alpha males tend to be those who are very polite, confident, and funny. My best advice is that when you talk to people, always look them in the eye--if you don't already do that. It sounds stupid, but it's very important. Make a conscious effort to do this and to be polite by saying things like, "Good morning", "Good bye" or "How are you?" I'd say it to everyone you see. Avoid broken phrases like, "what's up?", "see ya", and "hey". If a conversation ensues, smile if appropriate and speak slowly, be sincere, and look in the eyes. Feel free to be self-effacing, since those are the only types of jokes that don't offend anyone else. Jokes break tension. From a guy's perspective (and I may be dead wrong) I find that women's minds work quickly and they are constantly analyzing themselves and yourself during a conversation. Maybe men do that too, who knows?--I know I can't do it. Make sure you are always honest; but that's easy. If you find yourself talking to someone for a long time, you will have to run the gambit and informally ask her out (eye contact!) before wasting too much of her time--but ask politely without much pressure. The key thing is that if she says no, she may seriously regret it a few hours later and torment herself for turning down your offer of a light date. So it's best to remain polite and to be your best self the next time you see her. If you have another conversational encounter, feel free to ask her out again and see what she says. If she says no again, just her let be the one to ask next time if she ever does. That's really the only way of knowing: indirectly and informally asking. Reading body language can work, but some women are shy and unknowingly give off negative signals.
Women often say they like "shy" guys, but I think what they mean by this is that they actually prefer polite guys or guys who have personal hobbies and who are not overly-cocky or encumbered by a thousand buddies.