Change Your Facebook User Name before it’s too late.
The people who were not able to change their Facebook Username should change it Very Early Because Facebook is Allowing one time Change of the Username. You should Go Straight to Facebook and Change your Username in the you Profile Page (Not Settings).
Some of My ideas to Set a Good User Name
1. Use Capital Letters like iHarkunwar
2. Use Short Usernames
3. Using dots will also open your Facebook URL without Dots so you can Add dots.
4. Don’t Use Numbers as it Doesn’t look Good