The best advice I have to "make it" in the world? Be so good they can't ignore you.
The source of that quote isn't important. What's important about it is how you apply it to your life. Neil Gaiman, author of American Gods among other famous works, is known for giving a similar spin of advice to those asking for it in hoards. His advice is to be prolific. Write so much that publishers can't avoid you. Write so much that an audience spontaneously forms around your work and you wake up one day wondering how you ever managed to get this many readers. Work and don't stop working because that's how you get better.
It doesn't apply just to writing. It applies to everything. If you're working on a business, if you're working on becoming a writer, if you want to be a photographer, if you want to be a body builder, or even if you just want to feel happy in life. Keep your head down and grind out your work and you will get better. Keep putting your work out there and everything will naturally come into focus.
There's a Buddhist teaching that says that you should trust in the world to provide for you. When a bird wakes up in the morning it's not worried about finding a mate, or finding food, or finding a place to sleep. It just goes out into the world, fully trusting that its needs will be taken care of. In the same way, be that bird. Go out into the world and work hard. Do what you do best and things will fall into place for you. It sounds silly but it works.
Whatever you're doing, be it writing, music, photography, building a startup, whatever: don't do it for the money. You know who does it for the money? People who become fads and quickly die out. In the internet age where fads and memes come and go so quickly, pursuing a goal with the explicit goal of money works maybe 0.1% of the time. Maybe. If you're lucky.
Those who work hard reap rewards. Stephen King has written and published a book almost every year since 1974. He's published at least 72 pieces of work. That's more than years he's lived. Do you know why he's one of the most famous authors of the 20th and early 21st century? Because he grinds every day for his craft. If you can't find time every day to grind at your craft, you'll have a hard time making it.
"Making it" is entirely subjective. Find your definition of success and don't stop working until you've achieved it. Keep going, you're closer than you know.