SPRITERS, DOES THIS LOOK ALRIGHT?

My advice is unrelated to the animation, since generally I think idle poses usually shouldn't be animated. That's just my personal preference because I think it always looks silly. So I don't have any advice on how to make the bobbing up and down look less silly, because I don't think that's even possible to do.

Her shirt is suffering from a serious case of pillow shading. Her legs too. On her arms it's not as noticable because they're only two pixels thick, and on her face it's not as noticable because it can be interpreted as the shadow of her hair, but it's really happening over the whole sprite.

The solution to pillow shading is to define a light source. In 99% of cases this just means the light is coming from "upper left" or "upper right." If you can help it, you don't usually want it coming from directly overhead, or from the same direction as the camera, because it doesn't look as nice. Angled lighting helps your shapes look more defined. You also don't want the light coming from behind the character unless you're making special sprites that are only used in a dramatic scene with a sunset backdrop; that looks cool for one scene, but if used for the whole game it lowers visibility.

If you're planning to use the RTP graphics in RPG Maker, I would recommend an upper-left light source because that's what the RTP tilesets use (although almost every RTP tile is a perfect cube, so if you remove the auto-shadows then it's hardly noticable). If you're making all your graphics from scratch then upper-right will work just as well, but pick one and stick with it.

If this battle sprite gets flipped during back attacks or something, then it'll be lighted from the wrong direction when that happens, but fortunately nobody cares. Even professional spriters just let that happen, and no one notices. As long as it looks right at least half of the time, it's fine.

Additionally, I would recommend doing something else with her non-sword arm, especially if you keep the bobbing up and down animation. If you change this into a non-animated pose, then the arm being where it is would probably look fine. Flipping her arm so that her hand is pointing outward would be the easiest solution, though I'm not sure it looks any better.

I'm not really a very good spriter, and there's a lot of other info about color palettes and stuff that someone else might be able to give you, but pillow shading is something I do at least understand. I took a stab at fixing the pillow shading on the first frame your sprite so you can at least see what I'm talking about. I won't claim I did a good job but I feel confident that it's at least not worse than yours, heh.



Zoomed in:



One thing you might notice I did with the shading is fudge a lot of the outlines. I don't think there's anything wrong with outlines around each of the different-colored areas of your sprite, but lighter regions often look better with lighter outlines, especially if they're only a few pixels wide. You instinctively did that yourself in a few places in your original sprite, but I changed the placement of the lighter outlines to match the lighting, and even removed one or two pixels out of the outlines in a couple places where it could be mistaken for shading, like her shoulder and parts of the left edge of her shirt.

I didn't change her hair or shoes at all. They seemed fine to me.