- don't login into Google Account

- don't enable GPS, because every time you enable it, you get a popup suggesting you share your location with Google. If you choose "don't ask me again", the button "decline" gets disabled so that you cannot choose a wrong option by mistake [1] (I wonder, why Google wants to know where I am going to so badly? Did NSA made an offer they couldn't refuse?)

- don't have spyware from a manufacturer (noname Chinese phones often have it)

[1] https://android.stackexchange.com/questions/115944/in-lollip...