Ah, this is pretty ironic, but my means of doing digital art crapped out on me so I don't actually have a means of showing what I mean by what I say, but I'll try explain in a way that makes sense.
I'm curious what app you're using to make art? The thing I notice immediately is the resolution on the border is not very good, if I were doing this project, I would advise drawing one of the 'corners' of the surround, then duplicate that layer so you've got 4 of those corners, then rotate them using the edit or transform tool in your app, so you've got all four corners, in their respective corners. (of course you will have to use flip and rotate too to get them all in place) I'm not familiar with using premade assets for art, so I can't really speak to it, but, I honestly think for the most part, the most painless way of doing things, is doing it yourself.
Now, I think the next thing speaks to the fact that you're used to traditional art. The process of colour selection is so vastly different in traditional medium than digital, so of course it's difficult to adjust. I think something I was guilty of for a long time, was having my values way to close to eachother. When you're used to traditional art, colours always naturally appear quite differently, if you have to mix paints, you're going to change the value a lot more than just using a slider on the computer. Here, all the values used for the skin are way to close together, but also, something thats true in digital art is true of art as a whole - black is never black, white is never white. Using the 'true' form of any colour digitally is just way too stark. I heartily suggest that your black is always just a really dark version of another colour, in this picture I'd likely use a very dark purple for all the black in the image. The viewer will still think it's black, think about it, most 'black' items in real life are not a true black, they're just a very, very dark version of another colour. However, more importantly in my opinion is letting your whites be dark too. The whole image scews very light and glary, because the brightest colour in the image is just way too bright.
Ok, I felt I couldn't explain my point very well, and well, thankfully since there's no line work involved my tablet works well enough to show my point - I apologize for redrawing your pic, this is basically just to show that you can use values that are both way darker, but also way lighter, and that it will communicate the same point. if you use the eyedropper tool on this skin you'll see that it's way darker than on your girl, but by making the lightest colour in the picture darker (the whites of her eyes) it still communicates that this is a pale skinned human. Even the palest people are actually not as light as people tend to draw in pictures - except in certain lighting conditions, bright medical lights etc.
Anyways, keep it up, digital art is hard to get into, I'm definitely not great at it myself tbh, so you'd do better to learn from the best lol!
since your pic has no outlines and is more painterly, I think looking at artists like kawayoos process will really help you understand how digital art works. Looking at speeddraws honestly helps a lot.
It's way more helpful to pull information from a broad range of sources than focus on just criticism of your own output.... so always keep studying and don't get discouraged!
