That's a high color count actually, looks like JPEG artifacts, and this is something to avoid. Save as PNG. For small pixel art, like this, something like <12 colors is enough. Good job on keeping the sprite readable so far though, looking forward to where this is going.
Legs: blocked them in, first as "bones". At this step you want to make sure proportions are correct both between leg segments, and the figure total (about 5.5 heads here) and then flesh them out. Feet should appear to be on the same ground plane, you can usually eyeball this, but sometimes drawing it out helps.
Then went from b/w (3 colors) to color (9 colors), not sure if you were gonna do this step though. Tips when shading: Highlight colors are warmer (more yellow/orange) than shadow colors (more blue) the lighting conditions are relevant here, an open setting means the sky color is reflected in the shadows a bit. The darkest color is used for defining a core shadow/terminator (areas receiving little to no light, usually when there is a jump from light to shadow) here, you can see that on the right side of the poncho and pants. Also, try not to rely on outlines when shading especially on small sprites like these.
