I am looking to sell this phone Does it have any value? It is less that two years old. If it has value, what is the procedure to clear out everything in it and not mess up my Google account?
As for clearing everything, just do a factory reset from Settings > Backup & reset. It removes everything from the phone, including your Google Account. Everything that's saved to your Google Account (cloud photos, contacts, etc.) stays in the cloud when you sign into a new phone. Not everything gets saved to Google though, like SMS messages, so you might want to find a way to back those up if you want to keep them.