iOS Marketing and Advertising?

[firewood]

Are any developers willing to share suggestions about the most effective ways they've found to market apps (outside the App store), and/or to place paid advertisements?

Given, that with well over 10k apps in the store, the top 100 lists are really only meaningful to around 1% of all apps, what's the most effective thing to do when targeting the the top 10% of the market?

Thanks!