I have no good template, but I have the best app marketing methods for you, app of them are proven effective and efficient. Details as follows:
Get Featured On Mobile App Review Sites
There are many sites you can submit your app, such as cnet,mashable, techrunch, app advice, appbrain,etc. If you get featured on The Next Web, you can expect tens of thousands of unique visitors in the first 24 hours to hit your website and your app store page.
Apply for Awards
There are lots of organizations that give prizes to new, innovative applications for their functionality, design, and so on, such as Appy Awards, Best App Ever Awards, AppCircus competition, Apple Design Awards, Appsters Awards,etc. By participating in app awards, it can give you tons of press, exposure, reviews and plenty of downloads.
Boost App Ranking to Top 10
Over 65% users discover new apps by searching in the app stores, and most of the just browsing the top 10 apps. Then the best way to promote app is boosting your app ranking on the app stores. There is one "hack" way to boost app ranking, it's buying app installs, it can boost your app ranking in hours, highly recommend.
95% users would like to install an app has more positive reviews, especially for new apps, and 88% users trust reviews as much as personal recommendations. So the reviews have a great impact on app downloads, it can increase the download rates efficiently.
Hope the 4 methods are useful to u.