Here are a few tips about the Play Store that I learned the hard way by publishing my own programs there:
You can make a paid app free, but you can’t make a free app paid. If there’s any chance you might want to have a free (light) version and a paid (pro) version of your program, then create them both up front. Never take anything away that you put in the free version, or you risk a firestorm of protests.
You won’t be able to buy your own paid application using the same account under which you published it.
Read all the comments left by users, but don’t hesitate to report especially rude or vulgar ones as spam. Keep your comment area clean for useful feedback, both positive and negative.
Don’t get discouraged. People can be cruel, especially ...