in what can i improve my art and what are some tutorials you'd recommend

[vocal silo]

these are some of the most recent art that I've drawn (not that is recent really), and i'd like some comments abt it!! mainly shading/rendering cus' i do not know how to do it lol

[sinful lion]

First off, I love how crisp your style is!! I'm a fan of the lighting in shapes in the second and third piece, and the energy in the first. I think you're heading towards a really good direction in terms of shading & rendering.

If you want to take it to the next step, I recommend thinking about volume, form, and how lighting/shadows wrap around 3d shapes!! the best example of this would be your first and second piece. You can see the transition of the light on the fingers of the first, and on the face of the second through different value steps.

I would also recommend playing around with the relationship between soft shadows and hard shadows, basically mixing soft and hard shading to better explain forms. Your pieces mostly consist of only soft shadows or only hard shadows.

Here's a square to demonstrate hard and soft shadows. Hope this helps, let me know if you're confused on anything or need anything else!!