The thing I’d change is your palette, because it contains too many shades of similar colors, you don’t need more than 4 for the wooden part of the bow, and make them more contrast-y. Also try to give it a bit of cylinder shading, it looks a bit flat currently. Since it’s only 2 pixels wide, just make the pixel to the left (the one closer to your light source) brighter.
You also have some “breaks” in your arcs. Generally, when doing objects are are supposed to be round, you follow an algorithm how many pixels down you should go with the next row/column of pixels. You have a 45 degree angle edge on your outer contour - it’s fine if you want it to be there, but it shouldn’t be there if the bow isn’t supposed to have any edges.
You’re getting better, keep working on it! :3