It'd be easier telling you what to fix if you showed us your profile, your pictures, and an example of messages you send.
A few pretty good dating profile guides with the basics:
http://www.wellcultured.com/sex/138/how ... ng-profile
http://www.onlinedatingmagazine.com/art ... etips.html
As for messages, remember that you can't disqualify yourself, since you are on a dating site for a reason, and so is she - Just act comfortable doing all this and get to the point of what you want. Tell them why their profile intrigued you (Common interests, etc - don't mention looks, except maybe smiles and "you seem like fun" and such) then say that you are interested in getting to know her.
Don't look for IOI-s right away - all she knows about you is your profile and your message. If your message was funny (it's good to communicate a fun vibe) and/or contained smilies, and you get smilies back, you can take that as an IOI, and maybe if she points out what she likes in your profile, but don't expect more and take those for what they are worth.
Also, don't seem like you want to send messages for too long - get to the point of meeting in 2-3 messages.