So many app marketing techniques shown on YouTube... there's a lot to learn therte. If you are ina habbit of learning from video (rather than just reading), here's a list of good sources:
Business of Apps - Panels and presentations from the App Promotion Summit
MobileDevHQ - Discussions on App Marketing
Tap for Tap - Interviews with indie game developers
Casual Connect - Conference on game development and marketing
GameHouse - Game publisher
Application Developers Alliance - Industry group about app development and marketing
I've taken this list from Appmarketer, and they all seems pretty good sources.