Hi talin, welcome to the forum.
I think the first thing you should look at is contrast. Contrast controls priority for the eye, that is, what order the eye takes things in and to what degree something is focused on. High contrast makes something loud and unavoidable for the eye (high priority), while low contrast dulls it and makes the eye skim it (low priority).
Taking a look at your piece, the contrast between the white outline and black background is extreme, and thus traps the attention of the eye, while the actual form of the character is low contrast and thus is ignored. This has the effect of destroying detail and form, flattening the object so it resembles a cardboard cutout. Try removing the white outline and increasing the contrast within the character itself. Quick example:
From there you can add more contrast by adding more tones/colours. This will give you more range to define the form, too:
And yeah, crop your canvas.
