The outlines look like stroked, and thats not the corrent way to create them. If you are using Photoshop for vectoring, proper way is to do with pen tool. Also some colors could have a bit more contrast, screenshots often lack in them.

hmm i'm not so good at explaining vectoring and i somehow creat my own style while vectoring using broad and thin lines. But you tried to be correct and make propper lines. For your first time it isn't bad. I'm not really good at explaining things like akiranyo but when you really need help with vectoring or how to begin i would look for some videos at youtube^^

It's decent, but the dot for a nostril is a bit unsightly, try making small crescent shapes with the shape tool for details like that, it might not sound like much but it adds a lot to the image in the long run. It's also important to state what software you used.

I also would like to recommend to to rework with shadows on her face. Because there is always shadow from hair, so don't be afraid to add some more. I saw your shadows, but they are too weak. True to make them more expressive.

For your first time, this vector is okay. I would suggest not using a tablet in the future, though.

Reading over the comments already posted, I can only suggest (unhelpfully) time and practice will help to "feel out" your style.

The basics of the picture looks good but the left side of her face seems bland or flat. Vectoring doesn't always mean flat so try adding a little dimension into her.