Odds of Getting In
Cracking into this business is going to be harder than opening a walnut with bubble wrap. Probably. (It's not like we've tried.) The great thing about YouTube is also the worst thing about YouTube: "Hooray, I have the same access to this network as Kim Kardashian. Boo, so do billions of other people."
Think of it like a static-to-noise ratio—there's just so much stuff out there, it's difficult to get seen. And if you do get seen, you just have to hope it's by someone influential.
You can marginally improve your chances by learning about keywords and online marketing, but Google and YouTube have been around long enough to iron out any real exploitable wrinkles in the "level playing field" philosophy of the site.
The number one factor that isn't luck is quality, of course. The better your stuff is, the more likely people will want to watch it. We know—easier said than done. Even if you make something you find interesting, it doesn't mean anyone else will.
And even if you make something almost identical to something with a proven track record of getting hits, there's no guarantee you'll have whatever je ne sais quoi propelled them to the front page before you.