Working with Cover Art is more of a compositional thing than drawing skill.
When we're thinking about composition, we're looking at very very simple elements of looking at a picture and what the eye does. The center is the focus point (or the first point), then the eye will follow where lines on the page lead them. Then we're paying attention to how clashing/mixing colors make it easier or more difficult to see what you want them to see.
Compositionally, your covers are very good, I wanna get that out there.

So even without knowing the exact specifics of this project this cover gives me a good impression of what to expect. There's a lot of vertical lines for the eyes to follow. Obviously you'll follow her body then then letters, and you break up that monotony with a fun diagonal blue value.
You've got a career in design ahead of you.
The english text is mundane, and that's perfect because it forces us to imagine. "How could someone write a story about a statement like that? This'll be fun to see." That's generally what rings in your head.

You've got a bright background, and overall high-key characters. It was smart to make the text black. The only concern is it blends with some of the shadows on the characters. So there are letters that are easier to read than others.
What I would do in this situation, is add a glow effect to letters, or that white outlining, you have the last cover. That way each letter would have an equally bright background behind them. This would also open doors to use other colors like a darker blue, purple or green.
Also, this picture feels
ice cold. And that's good. Because they're at a snowy cold mountain, but what's happening is you're using all cold colors in this picture. Blue and Greens. So if you wanted to make like a picture of hell with all the fire and stuff you would use mostly, orange, red, and yellow and it would give the impression that the picture is very hot.

Also in this picture the focus point is on the character's face, whereas I think you want it to be more on the mountain. One way to help do this is like you've done and have a character look directly at the mountain. The eye will follow the character's eye in order to see what they're looking at. You could also bring the mountain to the center and put the words on top to fill that space, but that might require you to push the characters down farther and crop them more. Or push them back out of the foreground and into the middle-ground if you wanted to avoid cropping them.
Hopefully that helps your future cover work. I would try and focus on rendering the characters better. I can tell you got the skill for it. Even within the boundaries of your very fun style, there's still room to improve.