The ability to be versatile in your writing is bound to result in a sale. Oftentimes we get locked into a certain genre or refuse to try non-fiction. When I first returned to writing, I was focused on fiction and didn't want to even consider non-fiction. After doing a little market research, I learned there are job opportunities for writers that range from advertising copywriter to video scriptwriter and everything in between. Further research shows a very small percentage of magazines and books, out of hundreds published, accept fiction. Editors accept, on the average, three to four times as much non-fiction as fiction. Yet, they report receiving three to four times as much fiction as non-fiction. Editors are very clear they are looking for manuscripts to buy, but they can only choose from what's submitted. If you want a sale, you have to write what editors need. If they need more non-fiction, then write non-fiction. This doesn't mean you should give up your dreams of writing the next great novel, but what it does mean is you should plan to be more versatile in your submissions.
Work on that novel, but send out non-fiction articles too. Books abound about how to actually earn money as a writer. I suspect most, if not all, will tell you the same thing. You have to be willing to write whatever is needed if you want to get a check be that newsletters, ad copy, parenting tips, children's articles, or poems. Versatility is the key to repeated sales.