Take action. It isn't what you can do well that makes you money, it is what you do. No matter how well you are able to do something, if you aren't out there doing it, you won't get paid for it.. On the other hand, if you are doing something, even if it is only mediocre, you can earn from it.
Every day people are earning money from websites that aren't very good. But, the important thing is that they are up, on the web. They aren't still in the planning stages, never written, because the would be publisher is still comparing website hosts, doing search engine optimization, and worrying if the articles have the right format and word count.
Musicians and other entertainers get paid for live performances. They also make CDs and DVDs and sell them. I use the terms "musicians" and "entertainers" loosely as I'm not sure they are good enough to be called that. But, the fact remains, good or not, they are making money from what they do -- because they are doing it. They aren't waiting until they take voice lessons. They are out there singing and performing now.
Same goes for writing books. I planned to write books on full-time RVing and on making a living while full-time RVing. While I was taking notes and making rough drafts, making sure I had enough information, and worried about getting them properly edited, other people wrote and published books on those topics. Some of those books I've recommended -- because they were done and out there, available resources -- even though I believe that my books would have been better.
Every day people sell jewelry they've made. They sell their paintings, drawings, and pottery. They sell clothing and woodworking. It's not necessarily because they are great at making those things. It is because they make them and get them out for sale. They don't just think about it, they take action.
People earn a living as public speakers, personal coaches, and story tellers because they have the guts and gumption to do it. People get paid for planning weddings, catering meals, and taking photographs. Again, not because they are experts. It is because they've hung out their shingle and asked for people's business. They take action. They just do it.
You can waste away planning, preparing, and perfecting. If you are going to earn your living or supplement your income by doing a particular activity, you must actually do it.