Start with people who have already done what you want to do. If you can meet them personally and ask, do so (and getting to meet them can itself be quite a task). If they're historical or inaccessible, learn about them. Heroes and role models really matter. Find "a man to be emulated and admired".
What you'll sometimes find is that they'll teach you to not do what they did. For example, I'm a guitarist, and a very good one. I work hard at it. I had the opportunity to have a few conversations with the greatest guitarist I've ever met, and extraordinary musician. What I found out is that he's a very small person in a lot of ways. He practices or gigs about 12 hours a day, every day. He can't talk about much other than playing music. At that, he's tremendously deep. At everything else in life, he's a wreck.
What you'll sometimes find is that they'll teach you to not do what they did. For example, I'm a guitarist, and a very good one. I work hard at it. I had the opportunity to have a few conversations with the greatest guitarist I've ever met, and extraordinary musician. What I found out is that he's a very small person in a lot of ways. He practices or gigs about 12 hours a day, every day. He can't talk about much other than playing music. At that, he's tremendously deep. At everything else in life, he's a wreck.