When I ask an artist what is their favorite thing to draw or paint, and they say, "everything", I generally throw up in my mouth. If this is you, stop reading right now, get a gun and shoot yourself in the face. No seriously, do it now and get it over with. This will save you the pain of trying to make it as an artist.
Or worse, some artists I know do comics and when I see them in three months it's murals, and next week it's t-shirt graphics, and so on. When I ask which do they enjoy the most they either give some pie in the sky answer like I love all of them or how they're equally as good at all of them so they don't know. That's the equivalent to a medical student saying I could be podiatrist, gynecologist, or a rectal surgeon, they're all the same. No, they're not.
If you want to be a professional artist by running your business by being good at everything, stop now and work for someone else the rest of your life. You may not have to shoot yourself in the face, but you will wish did at some point. If you're going to be an artist you need to focus on what you love doing the most or at the very least one niche or area of focus. Why?
Generally speaking almost all artists can draw and paint just about anything, so you need to stand out in a very crowded and noisy marketplace. So let's say your thing is drawing fairies, market the hell out of your love for fairies. You could love drinking Orange Crush or the be the biggest Star Wars fan around. The point is most people will find you because of what you are passionate about. If a person searches for fairy artists you have a better chance of showing up versus a boring "artist" search.
Look at it this way. I just googled artists and Google returned over 1,010,000,000 results. I googled fairy artists and 20,700,000 results came back. And the more specialized you get, the fewer results will be in your niche. And by the way, generally speaking, you can charge more.