Instructions
Turn on your Xbox 360 console and log in to your gamer profile. Go to the ̶0;My Xbox̶1; menu, select ̶0;Profile̶1; and then click on the ̶0;Customize Avatar̶1; option to begin modifying your Xbox LIVE avatar.
Click ̶0;Change My Features̶1; to change your body and facial features, click ̶0;Change My Style" to change your clothing and accessories, click ̶0;Marketplace̶1; to purchase accessories, costumes and outfits or click ̶0;Choose New Avatar̶1; to start over with a brand new avatar.
Click on the ̶0;Save and Exit̶1; button when you are done modifying your Xbox LIVE avatar to save your changes and close the avatar modification menu. You will now be returned to the Xbox 360 home screen.