Thanks for the reply! I have infact been talking to users as well as watching the logs and analyzing google analytics data. I do have some insights on whats missing but as I said, the real challenge is in designing interfaces that can solve these problems. For example how do I display primary and secondary information on a profile page. What should be emphasized and de-emphasized. Since these are common problems, I was wondering if there is a book or something that I can readup to get some answers/pointers. Profile page is one example. Pages like account setting or stats page are other common pages that should have some standard design patterns.

In regards to books, I would recommend at least checking out Steve Krug's Don't Make Me Think, possibly some other design orientated books and then read up upon usability in general.

For example, take a look at: http://www.usabilitypost.com/ or http://www.uxbooth.com/ and http://useit.com/

You may wish to find a usability consultant too, or look for someone who hasn't used your app before with experience in this area to give you a few pointers.