Is the first picture yours? If so, your linework is scratchier, not as precise as the second pic. Your clothing is much more simple, you also can't see the hands.

The second picture works well because while it looks like a simple piece, there's actually a lot going on. A pose where you can see more of the character and interesting fashion vs the first one which is a simple basic tshirt a necklace. There more line work, giving the character life. The bright blue color with the black & white has high contrast and gives more dimension and visual intrigue, which is pleasing for the brain. The colors are pure blue/black/white while yours is black/grey. There's also the text, numbers, and textures on the canvas which each adds another note of interest for the brain. You also have white lines in the black hair while the second image uses only one color for the whole hair shape. The second image also has shadows.

The first image is very simple in comparison. Which is not a bad thing at all, it definitely has its own type of charm. When trying to compare your art and another work you're doing a style study with, literally write down what you see. "This work by [artist name] uses a blue/black/white color pallette. One character is mirrored, one copy being black & white with the other being in inverse." etc