No.1 you may use multiple accounts

No.2 do not use others email to make your new account

No.3 Do not use an offensive user name or a name that may make others uncomfortable.

No.4 You may not have spams in your username for example saying the same over and over.

No.5 You may have permission to use whatever avatar you like

No.6 do not use a disturbing avatar as it may make others fell uncomfort