>>1880054There are a number of things to take into consideration.
For the sweat/water marks keep them clear in the inside (remove the gradient). For the marks on the skin, make sure the shadow is inside the water marks, as well as outside. You forgot to clip out some hair coloring above her right eye. For the eyes, use the circle tool, and don't cut the bottom or sides of the circle. Have the white of the eye simply go around it. For the side eyelashes, have the tips curve in a direction, instead of being flat. For the mouth, connect the coloring at the tips of the lineart. If you're doing this in Illustrator, you can use Smart Guides (Ctrl+U) to help snap nodes to others. None of your shadows on the towel should have lineart around them. Have the lineart only for the outline of the towel. For the nipples, keep them rounded like they are in the original, instead of square. For the highlights on top of them, blur them so they match with the blurred pink/red areola. Keep the line for the belly button and stomach fold separate, like they are in the original. Keep the tips thin as well.
Many of your lines are too lumpy. Start each fill with the least amount of nodes. Only place nodes at the endpoints and any major curves. Make sure all nodes and handles are kept parallel. Play with handles to see how much they can fulfill a given area. Place nodes in between, if needed. You also lack curvature at the tips and endpoints of many of the lines, especially some of the hair. Use the handles at the tips more, and always be curving them in a certain direction. You also want the tips to be the thinnest, with it gradually increasing towards the middle, and either maintaining thickness to a two node endpoint, or reducing to a single node endpoint.
The lower lines, including the lines for the butt/legs and the pussy seem to differ from the original, and lack some detail. This is the original I was using:
https://chan.sankakucomplex.com/post/show/4898133.