Awww, a capybara bathing <3 This is really cute!
It looks like the main thing you should be working on is shading according to a lightsource. I'm not sure what the green object is supposed to be. It seems like a flat sticker rather than something in the scene. You're also overusing antialiasing around the capybara's face and the corners of the tub; AA shouldn't bridge the whole width of the line segment they're attached to.
Looking forward to your future works.
Thank you! That green object supposes to be a leaf
I don't it look alike a leaf neither hahaha but just doing it a bit in rush so just let it like that