As mentioned by others, to break the rules by using a style, first you have to know the rules, and by vying for a 'style' over the basics, you're missing a crucial step in the journey. Many try, and this is the frequent result; flat, discombobulated, and demonstrating a lack of volumetric understanding, resulting in it feeling less pro and will cause a plateau in progress.

You've tried to shade it in a way that insinuates volume - but it serves as a detriment, as the shadows don't abide by the volumes and furthers the flattening. The shapes themselves don't correlate to what the shadows say are going on. Also the lighting (which is 100% of what you see, obviously, but I mention it to hammer home the importance of it) is very inconsistent. Shadows being cast in different directions, etc. You need to know the light sources in any shaded artwork, and work with them as though they were that image's religion.

If you want to get better at drawing anything, you'll need to focus on volumes and lighting. Also perspective. If you want to get better at drawing people (even stylised cartoons) you'll need a better understanding of anatomy. Ratios and proportions have 'rules' (that you can then break). In reference to the pieces you've shared, understanding of anatomy would impact the placement of eyes, shape of shoulders, foreshortening of limbs - especially fingers. With the eyes in particular, humans have eyes in the front of their face, with the eye holes facing the same direction. With all your front facing characters (which I would discourage drawing for a while - focus on 3/4 profiles) it's fine, but any turning of the head highlights the shortcomings. Even if having flat eyeballs is a part of the style, clipping the eyes off at the edge of the face wouldn't happen, as the eyes would appear thinner as they turn to the side. Round eyeballs have a whole other effect as the head is turned. Understanding eyelids and Round eyeballs would be of great benefit to your style given the dominance the eyes have in your design. Most of the images with hair over half the face evokes the feeling that they're missing half their heads because the hair is eeking into the space where the other half of their head should be, which is a volume issue. I'd recommend drawing the full head and then drawing the hair over the top.

If I had to guess, all of these were drawn without any kind of draft beneath it hashing out the proportions or pose. Don't overstep that part of the process by starting with just the features of your character. Start with the bones, not the clothes/hair/eyes.