How does your craft make you wealthy? Through value. If you provide a valuable service or resource for your clients, you will make more money. The more valuable your work, the more valuable your time; hence, the more money you can charge.
Still, value isn't about being able to charge high fees; it's about making those fees seem small in comparison to the quality of work you provide.
So how do you make your work more valuable? Through expertise. You must strive to be an expert in your industry before you can charge the chin-dropping fees of your rich contemporaries. If you've taken a few online Illustrator tutorials or are fresh out of design school, you're not an expert.
Scientists say that it takes 10,000 hours of experience to achieve expertise in a particular area. That's 10 years' worth of applying your craft to many situations and working with many people who have very diverse needs. During that time, you forget the rules you learned in your early training and draft a rulebook all your own, each action contingent on the instincts you've developed after handling thousands of different scenarios.
You earn the right to be different, to reject contemporary thought and plow a path all your own. Your writings, words, thoughts and services are highly regarded and well respected. Having you on board becomes priceless, because you're an expert.
10,000 hours of hard work = expert. Where does that leave you?