Okay, so it's going to be a cover, so I suspect the empty space is going to be filled by text so I'll leave that. You already pointed out the lineart, and if you're new to a program, that really can't be counted against you
The first thing that stuck out to me is the lack of energy or personality in the pose. I can see a little bit of personality shining through in this character; he's a little confident, a little laid back, probably not too fussy of a person because he's in a a sweatshirt and sweatpants. But other than that there's not a lot going on. After seeing the sketch, I think the lack of energy comes from a lack of structure when sketching. Rather than building up the body in its entirety, figuring out the pose through gesture and placing the musculature on top, I feel like what you likely do is sketch out the basic pose(probably using rectangles and circles) then you draw the details like clothing, facial expressions, and hair, etc. right after. There is a gap where a more detailed sketch could be but isn't.
You can draw a person, you can draw one just fine. And the pose here is okay, but I also see issues in the details. The hand could be structured better, the ax is held in an awkward way where I think it's supposed to be resting on his shoulder, but it doesn't, and there isn't a clear light source. If the body was structured out first, the lines on the hood would make more sense because those lines would be based on how the fabric falls on the body. The hair, oh the hair. I think every young artist (and I mean young in experience) goes through a period of time where the feel as though they have to draw every strand of hair. Fortunately, you don't have to especially not when the rest of the artwork is not as detailed. The fact the hair is so detailed is very distracting.
Here's some recommendations on how to get better I guess. I'll say look up anatomy references and sketch those when you have time. Do multiple and do them for a while so you become used to considering structure when you draw. Watch some tutorials from artists who focus on the use of 3D shapes when drawing. Look at references for poses when you sketch so that when you want to draw a more interesting pose, your not making stuff up as you go. Also, look a clothing tutorial: how different types of clothes fall on the body. Lighting tutorials, practice on picking a light source when shading and keeping the shaping consistent. And lastly picking clothes, this is something I need to work on too. Maybe this guy only wears sweatshirts and sweat pants, but don't be afraid to change up the style every once in a while: expand that visual library.
That's all I have! I hope this helps.
