How to attract users to my facebook apps and games ?!

Developing an app or a game for the facebook platform is real easy and I have lots of new ideas for making apps, but the problem is how to get users after publishing the app. I use most of the viral methods in the market while developing the app, like sharing the output on the user's wall, tagging him, inviting his friends, publishing the app in the FB app center and stuff like that... But most of my apps have less that 1K users...
I'm looking for the latest FB app marketing techniques. Share your ideas here...

Sharing user's scores is really what game marketing is about. It should go viral by itself, if the games is good/interesting. Also you can pay someone who has fb pages with big amount of likes to share your game URL on their wall. Back in the days I did similar(didnt payed, friend had some pages with some likes, nothing special), reached 3k users in a day.... Games just shared some image on user's wall + game URL. Also im interested in fb app development, I have one game prepared, just need to bring up "social" part (score sharing, etc....). If you are interested in JV PM me your skype ID. In next few days will have much more free time that I have lately.
Good luck, baxxx.