I thought I'd share a few quick tips on getting more ratings, which I've picked up in my experience with Ludum Dare. Please note, I'm not putting this down as fact or anything, but merely expressing my own opinion.
Yeah, this one's kind of obvious by now I'd say. Your "coolness level" increases by one per game you rate, and the cooler you are, the higher chance you have of getting rated. Games are picked for people to rate both by how high the author's coolness is, and how low the number of ratings are.
Making your game web-based should get you more ratings; users of all operating systems will be able to play it, and web games are far more convenient for the rater. The rater doesn't have to wait for a download, or far worse, install various things in order to run the game.
If making a web game isn't a good option, then make the game cross-platform. There's a considerable percentage of people out there using Mac and Linux based machines who would greatly appreciate it.
Finally, never just hand the rater the source code and tell them to run/compile it. That's just bad. Also, try to avoid requiring libraries/frameworks to be installed prior to running the game, especially ones that aren't all that common.
While rating games, try to leave constructive comments behind for the author. Not only is this helpful, but it can potentially lead others to your game. This is because people can click on your name in the comment you posted and be taken straight to your game page. It's a nice side effect to being cool.
And that's it. Hopefully it was somewhat useful. In summary: