You probably do want to mix things up a little. I'm probably the last one who should be talking. I haven't been here long myself. But everyone says it does take time, and we're both learning, frankly, that it isn't as easy as we might have thought it would be.
But if you can widen the scope of your articles, different kinds of ads will be generated, and that might expand your potential readership, and then, maybe, possibly..... $$$$$$
You'll feel better when you get that first AdSense. Then you will be a professional writer. You will have the right to call yourself a freelance writer and add that to your resume.
Make no mistake. You will have the right to call yourself a freelance writer because, at that point, you will have begun to make money EXACTLY the way the newspapers and other media earn their money - through advertisements, their beloved sponsors! Keep your eyes on the prize and keep on hubbing.
Take it light, Micadeolu.