I think this is fairly well known, but the guys at OkCupid keep a blog[1] with their own research regarding how to improve your odds. There is, for instance, an analysis about the relation between attractiveness and camera: [2]

[1] http://blog.okcupid.com/

[2] http://blog.okcupid.com/index.php/dont-be-ugly-by-accident/

They used to keep a blog, but they stopped updating it years ago.

Before any speculation starts, one of the team members did explain why they stopped updating:

https://news.ycombinator.com/item?id=7028850 (12 Days ago)

They promised they would update it again once they were done with the book. But yeah, it's been a couple years since the last update.