I totally get where you're coming from. It took me decades to get the secret of talking to beautiful women. (Maybe I was a bit slow because I wasn't really a man).
The secret is...
Not to care what they think.
That's all there is. If she's into you, she'll respond positively (which may be flirty, maybe shy, may even be hostile). If she's not into you, she'll find a way to remove herself from your presence or make sure you get the message.
So DON'T WORRY ABOUT SEEMING CREEPY! Just speak up. Worst that will happen is she won't like you, and you haven't lost anything. You know they'll be missing out on a great guy.
I'm not saying to be disrespectful or impolite, of course, or to keep pushing when it's clear you're not welcome. But the type of guys who can go up to good looking women and open a dialog are those that just don't care about being shot down or seeming creepy.
I hope this helps, Harporho. I post this at great personal risk to myself. I fully expect armies of women who just want to be left alone to bodily cast me from womanhood over this advice.
Good luck. Enjoy being a guy.