This title made me giggle
You have to learn to walk, before you can learn to run. But at the end of the day it all comes down to content worth watching.
You can drag a horse to water, but you can't force it to drink if it's not thirsty. You can force your videos onto audiences, but they aren't going to watch if your videos stink. So a lot of it is learning the art of good content creation. Thumbnails and good interesting titles help.
But here's some extra perspective for you.
having 17 million subscribers won't guarantee 17 million views. Look at pewdiepie, he doesn't get 100 million views per video, so subcount really is unimportant in the grand scheme of things.
Secondly, if you suddenly get 17 million subscribers, you'll want to beef up your personal security. A lot of celebrities have some horror stories when it comes to fame, so ask yourself if you really want that in your life.
Once you become famous, you lose all privacy. Are you happy to give up privacy for the rest of your life?
Much better to enjoy a slower more controllable growth, and that comes from the long term journey of learning the craft of good content creation.