Sprites for a Friend. Need advice.

[StarSock64]

I agree that broken outlines are usually a bad idea.
If the blank spaces are there because you feel as though making those outlines in pure black is too harsh, I wouldn't disagree with that. I think a more proper fix, though, is to use a combo of black and a different color, like dark brown, to finish the entire outline without any gaps while making it  smooth

In the 3/4th view, I think you should try to get the highlight to match the shape of her head a little more. This might not make a lot of sense to you if you haven't had practice with it, but try to imagine the three-dimensional form of her head and how the light would react with it. I wouldn't say it's quite matching yet, so it makes her head look a little flatter than it needs to be. I would probably extend the highlight to the left a little bit, or something. It's kind of hard to explain with words...

I think the black outlines of the eye transitioning directly into the white is too harsh and makes those outlines look jagged. Some dark gray antialiasing or something of that sort would probably smoothen it out. Might want to add a small amount of AA to the top of the black outlines of the eye too, using dark brown or something.

Again in the 3/4th view, I don't think the positioning of the antennae is quite right. I would try defining the center of the head as a line that curves along the shape of the head, and then place the antennae on either side of the center using that guideline. The antennae should be equidistant from the center (but you should also account for perspective)

(if you need elaboration feel free to ask)