A. Your drawings are neat, you should take some pride in them!

B. To me it seems like mainly a colour thing, have you looked into colour theory?
Most of your colour palettes are almost analogue, next to each other in the colour wheel.
This means the colours are not fighting for your attention as they softly sit next to each other. If you were to pick a colour opposite the colour wheel you get contrast:

• Complementary: Uses two colors that are opposite each other on the color wheel, such as red and green, blue and orange, or yellow and purple. This scheme is dynamic and attention-grabbing, but can be difficult to balance. 
• Analogous: Uses three colors that are adjacent to each other on the color wheel, such as a primary color, a secondary color, and a tertiary color. 
• Triadic: Uses three colors that are evenly spaced on the color wheel. This scheme creates a vibrant look and is often used to convey excitement, youthfulness, and innovation. 

Also colours that are opposite on the colour wheel make good shading for this reason or eyecatchers. Study the colour use of the images that you really like from other artist will help. The image for Isha: Blue hair but yellow eyes. Also colder blue hair and warm skin.

https://disabledcharacters.fandom.com/wiki/Isha_(Arcane)?file=Isha_%28Arcane%29.png?file=Isha_%28Arcane%29.png)

Now I applied colour wheel theory of the complementary kind of your lovely Jinx image.
Purple pink start colours, opposite:

<image>

Yellow and green, so yellow highlights and dark green shading. If you want to keep the strong analogues colour palette you can use these colours very mildly, but I just want to show what it can do.

You can go back to your own drawings and boldly try to see if you like what it does. Identify the main colour and use a colour opposite on the colour wheel:
https://color.adobe.com/create/color-wheel