There's a lot of advice out there about the techniques and gear a professional photographer should be aware of and use, and while those are certainly good things to know, there's another aspect that often gets overlooked, even by seasoned photographers.
Coming to you from Daniel Norton, this great video talks about professionalism and reliability. My composition teacher always told me: "there are a lot of mediocre composers out there with careers, simply because they show up on time and deliver what they say they will." Of course, he wasn't advocating settling for mediocrity, but rather emphasizing how far having a reputation for being reliable and professional will carry you. It's easy to overemphasize other aspects of growing as a photographer at the expense of ensuring you're developing a strong professional reputation. This is why you hear a lot of successful professionals say that being a photographer is really about being a problem-solver, because at the end of the day, your paying client doesn't care that it's raining or that your flash just died; they want the results they paid you to create at the expected time, no excuses.
Lead image by rawpixel, used under Creative Commons.
Running a business. That's it. Nothing else.
The fact that the guy in the video constrained his statement to the deliverables would suggest he still doesn't get it. But hey, I'm sure the IRS will be really cool with non-payment of taxes when he explains.
But sure, let's run with his premise. Anyone who has paid any attention whatsoever, knows full well that skill doesn't really factor into being commercially successful. After all, there are a great number of average photographers, who are commercially successful.
Anyway, all that aside, if you want to become a professional, then you should go and take a small business course; ideally, where the syllabus covers accounting, networking, and marketing. Additionally, contract law and copyright law are both valuable knowledge sets with regard to professional practice, and should therefore be covered in any education.
As to the deliverables (the photos), experience will teach you, and you will learn.
Yes, he is right that photographers offer solutions or solve "problems".
But like Connie the bookkeeper used to say, the thing we get paid for is invoicing.
Sadly, it is all about marketing these days.