So you're about to create a new account, and you see the box to input your username. What will you type? The most important thing to ask yourself is: What will this account be used for?
1. The Business/Formal Username
If this account will be used for business or school purposes, you'll want to use a formal username. A formal username typically consists of your full name, or your first initial and your last name. If the your name is common, the username will probably be taken. In this case, it is fine to add a period or underscore to split your first and last name. Or, you can add some numbers to the end of your name. Don't do anything with this account that you wouldn't want a prospective future employer to know about.
2. The In Game Name / Gamertag
This will generally be your alias for games and forums. To make a good and lasting gamertag, you'll want to create a unique username, one that nobody else has. You do not want to simply add numbers to the end of a username that has been taken. To make sure your username is unique, search it up on Google. If you get any hits that aren't yourself, pick another name. If you have trouble thinking up a username, search for lists of prefixes and suffixes, and just combine some of them.
When using this username, you generally do not want to give out any of your real personal information, except maybe your first name.
3. The Hacker-handle / Burn Account
This username is used for things your probably shouldn't be doing, things you don't want people to know about, or you're just creating a one-use email to sign up for another account. It really does not matter what you choose for your name in this case, even random numbers and letters is fine. Just make sure it doesn't contain your real name and is different from your gamertag. Make sure it isn't affiliated to your real identity in any way. You'll also probably never want to use this username ever again.
TLDR: Think ahead into the future and make sure you won't regret your choice of username.
