I created a new Google account. How can I migrate my android device to use this new account?
You can have multiple Android devices signed in to your Google account, as observed in Play Store's Device Manager:



You can also easily remove your account from your friends phone from Settings -&gt; Accounts &amp; Sync, where you can also instruct the phone not to synchronize your sensitive data with his phone (ex. sync Family Calendar but not App Data or Contacts!)

In this screenshot, the "Remove" button is on the top-right after you hit your menu key.



Hope this clears up your concerns!