I recently thought i should do a challenge for myself and decided to draw lots of anime characters from anime scenes. To improve my knowledge of facial types and also gain better understanding of coloring. So i drew this one.
ORIGINAL:

MINE:

After finishing this drawing i thought, mine looks bad. So i wanted to seek help from you guys.
First off, i want to ask, what things i should work on and any tips and tricks you give would be appreciated. Secondly, I have some questions of my own. Hopefully you can spare some time for me. Thanks in advance.
* As you can see in the below images, there are problems with my lines. How can i improve it?


Also, here are my brush settings since probably i need to work on it too...

* I also am wondering if i am doing something wrong with resolution or size of my inking brush. Res: 900x1400 and inking brush size: 3
* The color change here doesnt look right(White spots and weird color jumps?). What techniques can i use to improve it?


Thanks in advance and hope you have a nice day : )