The perspective doesn't immediately stand out as bad to me. I think the composition's weak, as a result of you starting with the character and not sketching in the rest of the scene. What are you going for with the background? Are you sure the character should be in the middle? Are you sure you need that much background?
It looks like you copied the shape of shadow from my texture example. That's fine since you did plenty of your own work on it, but consider if that shape and size benefits your piece. It doesn't correspond to the shape of the character, but it's also not very minimal, and it doesn't correspond to the light direction on the torso.
When characters sit like that, there are folds between the crotch and thighs. Check out the refs posted earlier in the thread, they should help. Even when a character is naked, there's a dip/fold there. Clothing just means even more folds.
The outline on the rug doesn't look good to me because it's lighter than the brown. Outlines should be darker than the colours they're separating. Otherwise, they read as blending/blurring/glow instead. If a dark outline makes that part of the image stand out too much, consider not having an outline at all.
You have perspective on the carpet, but not on the flooring, which makes the planks look like they get larger the further away they are.