I love the character idea ! great work on outfit too!

Enjoy

Right off the bat there are a lot of issues going on in here. Most notably is your shading, there is really no consistency to the way it is done, it seems you have a general idea for the base layer where the light source is (top right) but then you have these highlights placed randomly on all parts of the character that completely disagree with that. The highlights should only occur on the parts where the light is directly hitting and generally they'd contour with a certain area or are on an edge so the light would really be focused. The best way to wrap your head around that concept is doing still lives of various household objects under a single, strong light source.
Also problematic with your shading technique is that it is very limited and honestly quite boring. You currently really only have a standard color and then a slight shade of that color on any given area. you should try using multiple shades and tints to get better depth in your character as well as bring out the contrast a bit more. The character outline is largely unnecessary, but if you're going to keep it it should probably match the yellow bars going across the bottom or be different color, right now as is they're too close.
The way the legs get cut off is jarring and takes away from the drawing as a whole, you should really consider reformatting your composition to fit them on there. Back to the shading, I feel like its way too soft as well and combined with the outlines it makes for an unappealing effect. I would say either go full cartoon with sharp, crisp cellshading and keep the lines; or go full on render with a very well developed dark, to medium-dark, to medium... to light, and ditch the outlines.
On the character itself right now she is very much in the same color family throughout. She's all yellow, brown, tan and orange, the white, the red and the black are nice in that the break it up a bit, but more of that is definitely needed. Try experimenting with complementary colors as accents like jewelry or clothing patterns, they'll bring a lot of nice contrast out and make drawings much more visually striking. I get that this is fanart, but that doesn't mean you shouldn't make it your own.
That "nyaa" written there in a very basic font could also go, if you're going to include lettering in a drawing, really go all out, make the words feel necessary to the drawing, give them personality to accentuate the characters, using canned fonts, especially soulless canned fonts like that don't give any real insights into the character and just serve to distract from the focus.
Finally your signature/watermark thing is a bit too big, complicated and intrusive, for future pieces try streamlining that, make it smaller less busy and probably a bit more transparent. Make it a single color as well, the blueish fill with the white outlines draw way too much attention to it, better to just stick with white.
Hope that helped in some capacity, you have a lot of promise, definitely keep up the good work!