Favorite Sports Achievement
Select a sport from the Favorite Sports list to customize your Channel Guide.
Now for getting favorite videos. So you need to press to get to the settings. Now use the moving to the right to select your favorite sport. Once you select a favorite sport, or two, the achievement will unlock.
There is also a small bug where this may be unavailable (very rare). Try logging out and back into the app to see if it will reset. If this still does not work, try adding your favorites on espn.com and then restarting your Xbox along with the ESPN app.