Critique me

This is my second critique but that doesn't mean that I'm a professional or extremely good at expressing my thoughts.
Did you use a mouse for this or a tablet?
The shaky lines and colors could explain you using the mouse, but that's okay since digital art with a mouse is hard. ( well for me anyway).
The overall coloring is very flat. You could do more shading and highlights. The highlights on the hair stand out too much but if you tried blending it and do smaller highlights, i think the overall effect would look better! <img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" title=" (Big Grin)"/>
For shading, I think you should use more than one color so that everything wouldn't look so flat. The clothes folds could be more realistic but since you're going for the cartoon style, you don't need a lot of folds like in ani/manga or realistic drawings. There are many useful tutorials here! I can link you to some later! <img src="e.deviantart.net/emoticons/s/s…" width="15" height="15" alt="" title=" (Smile)"/>
Shadows are everywhere, and I still get confused about where to put them too. But judging from this picture, it seems like the light's coming from the left side. So the shadows on the right sleeve should be on the right.
To explain my ratings- this didn't make a huge impact on me since your OC is just standing and smiling. Which is a fairly common pose. (ditto for originality)
However, everything is unique and original. But the pose isn't working for me. Maybe you made her want to look this way for a change, i don't know, but it seems boring and she seems rigid.
When sketching try using a mannequin or draw a stick figure with joints and flesh it out later. (it helps for me! <img src="e.deviantart.net/emoticons/w/w…" width="15" height="15" alt="" title=" (Wink)"/> )
The technique- the lines aren't very neat and seems shaky. If you're using a mouse, Paint Tool SAI is wonderful for lineart! <img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" title=" (Big Grin)"/>
So to do it you should click on the little icon called " New Linework Layer" next to the new layer icon. Then in the brushes
panel, click on the curve. It's very to use. Try it out! <img src="e.deviantart.net/emoticons/s/s…" width="15" height="15" alt="" title=" (Smile)"/> And to color, use the magic wand and select the space between your lineart that you drew with the Curve tool, and on a new layer, use a paint bucket or a brush to color in! It's a quick and easy way to color. To do shading, you could do a new layer on top of the colored layer and click on the box next to "clipping group" so that everything you do on that layer would only stay inside the colored space. <img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" title=" (Big Grin)"/>
Hope I helped! <img src="e.deviantart.net/emoticons/b/b…" width="15" height="15" alt="" title=" (Big Grin)"/>