[youtube http://www.youtube.com/watch?v=q1AKVPeppZQ&w=560&h=349] It's every app developer's biggest problem: How to get people to actually discover your app. In a very popular session at the Android Developers Conference (AnDevCon) in Burlingame, California, Gary Yentin, CEO and founder of App-Promo, said paid media, which is advertising, often banner ads, is the most effective way to get people to download and use your mobile app. But getting paid media to work for you is a science, Yentin said. You need to constantly work it and measure and test and play with your creative content. His advice: Don’t rely on one traffic source: By utilizing several ad networks you’ll be able to reach your largest potential audience, achieve the lowest-possible acquisition cost, and protect your app’s brand from saturation. Measure, analyze, and tweak: If you don’t have time to manage your ad campaign, don’t bother buying paid media. Managing it and tweaking it is part of the process. Otherwise, you’re wasting money. Installing is not enough. They need to use it: You can pay for cost-per-install, but that mere install isn't your goal, especially if your app is ad-supported. You need people to use it. Track all of your users’ interactions within the app. Once you determine where the most loyal users are coming from, steer your ad spending toward those traffic sources. Vary up the creative: People will be staring at your banner ads sometimes all week. Don’t get stuck in that rut of creative fatigue. Offer up different creatives, especially seasonal ones. Have a version and offer for Christmas and other holidays.