To improve your Minecraft username, do any of the following (don't):
1. Adding an "MC" to the end of your original username.
(Some youtubers, like Grian, do this)
2. If you have a youtube chanel, add "YT" to the end of your username.
3. Put an underscore in front of your username, if you want followed by any of the above, or your favorite number.
4. Enclose your username in x's. Example: xXkeayXx
5. Your favorite food. Example: KeayStuffedCrustPepperoniPizza
These tips may or may not be suitable to your liking. But hey! I gave you ideas!