Qt for Android gives you an excellent leg up on mobile development, but it's not a panacea. If you're planning to target mobile devices, you should be sure to have a good understanding of the usage patterns for your application's users, as well as the constraints in CPU, GPU, memory, and network that a mobile application must run on.
Once we understand these, however, all of our skills with Qt Creator and Qt carry over to the mobile arena. To develop for Android, begin by installing the JDK, Android Studio, Android NDK, and then develop applications as usual: compiling for the device and running on the device frequently to iron out any unexpected problems along the way.
In our final chapter, we will learn about the bunch of odds and ends in Qt Creator and Qt in general, which will make software development much easier.