Like everything else, a proper plan needs to be thought of beforehand. This process includes designing the app itself, but before that, surveying the market and whether it would be accepted by the users.
Focusing on how a user would want to use an app, given the wide array of smartphones available today, every single detail needs to be taken into consideration to ensure that the Android experience is still there and not totally lost.
This is probably the most difficult process as it requires hard work, concentration and even more dedication to staying focused with an idea and going through with it. Those who have learned and gained experience writing Android applications, they will surely tell the newbies in the field that failing is a part of the process, so do not let that get you down.
Android makes it easy for developers as the APIs they provide to build apps allow the developer to take advantage of everything interconnected with the phone like hardware, software, internet and any external accessories.
To learn more, finding the Android Develop document will allow for a more in-depth and detailed instruction on doing so.
Once the app is completed and all troubleshooting, bug testing and finalizing has been passed, it is now time to put the app into the vast Android market. For newer developers, their first few apps may be totally free of cost depending on how they strategize it, but most of the time, a free test run is always given with features having to be unlocked through a purchase.
Other developers, who have established a name in the field and have well known apps on the top lists, move towards charging for a newer app right at the spot from users. It all depends on how you think your app will do once released into the wild.