Answer:
Just pick something you like. Mix and match names, things, and other stuff. Say if you like puppies or dogs, you could be:
Puppyluver
iheartdogz
puppydoggirl
If you want a name to be your username, you could be:
BrittanyGirl
TazminRockz
IrisHorseluver
But you might need a number after a username. If you don't want one, let me tell you something- a number makes in more "virtual-like" if you know what i mean. And you could always choose a weird username. But make sure you like it!
-------------------------------------------> Hope I helped! <---------------------------------------------