Sage's/Forte's Sprites and things

[StarSock64]

If you hadn't put that reference there, I would have never guessed that was Nui. You seemed to have missed a lot of important features

First of all, that gigantic bow of hers. It's pretty striking and distributes the colors more evenly. On that note, the hair color looks way too orange.

Next, her dress needs a lot of fixing. The way her skirt flares out is really important to her design (it's a big part of her silhouette). Instead, the sprite has a generic pink dress. I know nailing that kind of thing in a small sprite is difficult and you might need to make some compromises, but that doesn't mean you can just skip it.

It would have been good to try to work her eyepatch in since that's a huge feature, but it probably can't be helped. Her head still needs work though.

I think her skull might be too tall. Nui has prominent eyes. Making the skull taller makes the eyes proportionally smaller, so it doesn't look like her.

With anime characters like this, I think it'd be best to avoid portraying a protruding nose, since the style tends to downplay the nose a lot. The nose and forehead have become too prominent, changing the feeling of the character entirely.

I'd pay more attention to how her bangs look. You have them looking straight, but they are very much swept.

Also the hair is copy+pasted and ignores perspective. Doing that throws off any illusion of where things are in space. It's like when kids draw feet going in opposite directions in a front view. It wouldn't make sense! It might be fine to leave the left tail behind her body like that for readability's sake, but I would change the one on the right. Maybe make the left one connect to a more sensible spot on her head rather than arbitrarily putting it on the edge, but if you add the bow, it will probably fix that problem anyway.