I see a few guys cant get replies, your either not sending something worth replying to or your just straight up ugly. If thats the case then im sorry but this little line always work for me.

Hi, i believe attraction is 70% personality 30% appearance, what do you think?

see with this the initial contact does not show rudeness, it shows your not all about how hot the girl is (even though you are) and is inviting them into a little debate, something that stands out and draws the girl in for her to give her opinion.