The most important is that it does not matter whether or not you are shy, as long as you can ACT like you aren't. I learned this 20 mumble years ago when I started playing a "persona" in the SCA. While Larry was deathly afraid of women in mundane life, Lawrence in the SCA was quite a flirt. It took me some time to be able to actually make use of this, but eventually I learned.
Women actually like it when guys *politely* ask them out. I've actually heard foreign women loudly complain that American guys never make the first move until the women hit them over the head with a clue by four.
Being turned down by a woman does not actually cause one physical harm. I've asked many women out, and not once has one taken a swing at me for it.
If you don't give them the chance to say no, they won't have the chance to say yes.
I know that you meet lots of very nice, attractive women, because I see you at the places I'm at when I meet them.
It's not that women don't like nice guys, it's that they don't like wimpy guys. You can be nice and still not let people walk all over you. You can be nice and still be assertive.