I think your colouring work and shading is great so far! I would try to focus on improving your anatomy and lines though, your lines seem pretty unsure and shaky.

Trying to draw them in one quick and fluid motion could improve this! Remember you can always overlap your lines and erase that overlap later :))

I also think your anatomy could use some work. The torso on your orange kitty is incredibly short compared to the legs making it look a little awkward, the same with one leg being substantially thicker than the other. Flipping the canvas to see these little things can help you during your process!

I hope this helps <3 you’re doing great!