Ask Her Out In a Way That Makes You Look Interesting
You might want to consider a little trick I use.
Tell the woman that it was nice talking to her and kinda get ready to go away. Then, think for a quarter second, and tell her about something, maybe something you have an extra ticket for, and ask her if she wants to go.
I think the reason it's always worked great for me is it makes it look like you:
1) Have a lot of stuff going on in your life (making you look interesting).
2) Makes you look like you have a specific idea and action in mind (making you look like you are decisive and manly).
3) Makes her wonder who else you would take (making it look like you are in demand with other girls).
4) Makes her think she only gets to go out with you because you are going anyway (prevents you from looking desperate to go out with her).
5) Makes her wonder how much you like her (which is different than the typical position of asking her out and putting your cards on the table... putting her in the position of complete power).
It's always worked for me. The only drawback is you always have to have something in mind when you go out so you don't get caught unprepared. But it's always seemed worth it to me.