I am cofounder of Kidoteca ( <a href="https://play.google.com/store/apps/developer?id=Kidoteca" rel="nofollow">https://play.google.com/store/apps/developer?id=Kidoteca</a> )<p>We are yet to reach profitability, or have a awesome amount of downloads, but our total downloads so far in Android are above 50k, so we are not completely bad either.<p>First, if you have the money, throw money on marketing, really. Without money it is very hard to get far.<p>Second, Android tracks the quality of your installs, not only absolute downloads, so pay attention to the quality of the ad publisher you are using... we used so far:<p>AdMob: Solid, works well, expensive.
Facebook: kinda inefficient.
StumbleUpon: started only 2 days ago, so no data.
AppBrain: Could get a guaranteed download for 20 cents, and very fast, we could baloon the amount of downloads absurdly fast. But we noticed that the uninstall rate was also balooning, in the end after a while the active installs started to drop instead of increase, and our ranking plunged (and took 2 months to fix), so stay away from it unless you have boatloads of money to throw on it and use as initial download numbers platform.
Blogs: they don't do much on Android, on iOS it is better.<p>Long term: on Android all your apps tend to rise in downloads in long term if they are good enough, first because most apps on android are found by search, and android search is good (of course, this mean that if you have a crap SEO you are screwed), and Google Play take the app current popularity on its search ranking, as your app gets popular, it gets more popular. My apps usually are getting a 10% increase per week in downloads (at least for the first two months).<p>For launch, try to reach the "new free' or "new paid" in your category, it is not hard in several countries, and helps a bit, but don't focus too much on that, it is not a great thing like it is on iOS.<p>I have some friends that work in huge companies that make mobile games for hire. They usually spend the same cost of the app in marketing (ie: if you made the app alone in 3 months and paid yourself 3000 USD in monthly wages, spend 9000 USD in marketing).