Things You'll Need
Instructions
Log into your Xbox LIVE account from your Xbox console.
Scroll to "My Xbox" and scroll to your gamertag.
Highlight your gamertag, and then press "Change Gamertag."
Scroll to either "Enter New Gamertag" or "Get Suggestions," to create your gamertag. If you choose to enter your own, use your controller to enter your new gamertag.
Create your gamertag, wait for confirmation that it is available and then press, "Yes, use this gamertag."