For a guy of my small stature and ability to rouse concern in others still, I was actually really shy about asking out girls. When this situation occurred where my buddy's sister was getting married, (that reminds me, I need to mail the card for accepting her invitation) I started sending out practice messages of asking out the girls I didn't really care would reject me. Basically, it was to make them feel a little weird inside because it seems like I feel what a girl would be feeling so that was like my intuition for doing so, and I had fun.
After writing out those messages, I just copied and pasted my favorite lines to ask out the girls. I then went down the list and lo and behold, on my third try, I received an acceptance while the other two reached back to me politely decline the invitation. Now, I seriously have the feeling that those messages I sent to the girls who never got back to me, have had a positive effect for my situation. The positive effect is basically making them feel like a bunch of weird and crazy ladies.
Just flat out, I seriously don't care if any woman rejects my advances now because I can just move on while feeling a little sorrow. I don't care about feeling the sorrow because I believe that eventually I will figure it out and the right person is someone I will be able to form a good relationship with me. Obviously, the ones who are attracted to me and accept my offerings would be the best for me to work with.