What Kevin said, every bit of it. I would add that part of the threshold for getting signed was once being able to demonstrate having 100,000 or more followers. This is an old number. Members of Fleetwood Mac said once in an interview that they wouldn't be able to get signed now. My understanding is that Taylor Swift raised the bar (and set records) by attracting multiple millions of viewers to her offerings on Youtube.

Another thing that shouldn't matter, but does, is being young and good looking. Every once in a while a Susan Boyle or [exception of your choice--I can't think of anyone offhand] comes along and makes it big, but they have monumental talent to punch through this particular glass ceiling. Such artists tend to prove the rule by being the exception.

Maybe you meet all of those criteria; if so the best of luck to you (which would be another unwritten requirement).

Richard

"My primary musical instrument is the personal computer."