Money is a subject that is rarely discussed openly and that can be detrimental to anyone newly trying to make some as a creative. Here is an interesting and open discussion about the topic.
I used to often write on the topic of business and money as a creative, and it's something I ought to strike up again. It is undoubtedly one of the most difficult areas of being a professional photographer or videographer and yet one of the least discussed. Thanks to it being seen as a taboo subject for most (doubly so for us Brits, unfortunately) we have very little to go on when we first start.
I'll speak candidly about my first year as a professional photographer. I had just finished my Master's and had loans and credit card debt, as a graduate usually does. I was also looking to buy a house with my girlfriend as soon as possible. So, starting my own business — particularly one which has an infamously low average yearly income — was a rather large and stressful risk. I essentially knew that I had to make it work and extremely quickly. Despite that, I had no earthly idea how much to charge for any job, to cover all my costs, to run my accounts clearly, and so on. As a result, I lost money on multiple jobs I priced incorrectly and I didn't know where to turn to learn how to do better, so I just read business books, which aren't specific enough to practically help.
I always appreciate videos and content like this one from Rafael Ludwig's as it's important to open a dialogue about this topic and help new creative professionals to understand how the finance side works.
I have never had a problem finding sources of reliable information about earning money in photography. That's done by joining professional photography organizations and becoming acquainted with a network of those already doing it. Some of those organizations have specific programs that can even examine a photographers business records and provide specific advice.