Hi ! I'm not a professional or anything but I'd like to offer some advice!
First of all, your art is wonderful but I can definitely see some areas for improvement. For one, you could try practising anatomy a bit more as the heads look a little too big on the body (Although I'm not sure if this is a style choice tho ? I think that the full-body pieces look fine but you should focus on the bust drawings)
The effects you use in your drawings are wonderfully well executed but I think that what's dragging down your work could be the brush you're using to draw! I would suggest looking for a different brush because so far your work looks too clean and smooth and it would def improve your work if you used a more rough or diverse brush for the hair rendering. I like the subtle and smoothness of how you render skin tho! I also like the line art but I feel like you could improve with a different brush that'll add weight and some thickness to darker areas to bring out shapes better. Colouring your line art would make the pieces look soft too (optional but I think it is a nice touch)
Anyways good luck with your art journey ! Your art is wonderful and my fav would be the pink-haired girl drawing, I love the colour choices 💗💗