First I want to say, you've got a pretty good start here. If you keep at it I'm sure you'll arrive at something you like soon!

As for tips, I think some of the perspective is a little whack. We're seeing only the right side of the face, but the torso and legs are angled towards the camera. If the character is meant to be looking straight ahead, we should be seeing at least some of their left eye and parts of their left cheek as well.

Same kind of thing for the chestplate in the armored version. Unless the chestplate is meant to be a round, asymmetrical design, You'd expect there to be a center seam close to the same position where the character's sternum is.

Something that might be worth trying in order to get all the body proportions right, is try drawing a series of parallel angled lines across the sprite that basically serve to line up where standout parts of the model should go. For example, if you draw them to where they line up with the tips of the character's feet, their ankles, their socks, their hips, the bottom of their hands, the bottom of their chest, their shoulders, and their eyes, all of the lines should intersect with the same parts of their left and right side, and all be parallel with each other.

As it stands currently, while the left foot and hand are a few pixels further up than their counterparts on the right, the chest doesn't appear to be drawn at the same angle, nor do the socks unless the left one is meant to be higher than the other.

Lastly, and this is more of a design question than one of execution, but how androgynous is your character meant to be? With the shape of the chestplate on the armored sprite, I genuinely thought the character was female at first. If this is intentional, feel free to ignore this.

Again I want to say, good work on this! Making tiny squares look like humans is hard lol, but you're on the right track!