when you're doing pop-out sigs make sure there are natural borders, when we can see where your canvas ended and began, you're doing it wrong.
you've got a solid color scheme on the second one, try and carry it over to the first.
look at your render, see how saturated/unsaturated the colors are, and take it from there.
as for placement, try never to place the focal point in the center, that's a big no no when it comes to any art form, either take it to the sides or move it off-focus slightly, it creates for a much more dynamic image.
another thing i'd recommend, stay away from anime, it ruins any chance of having depth of field due to the constraints of such a simplistic design.
other than that, i'd say try more effects, vary it up, right now you're at a below amateur level and can probably try more advanced techniques.
