Heheh, she looks like she's really in the zone. I wish there were more modest pictures of Sona like this one. It's a nice picture, although I do have some constructive criticism for you, if you are open to it.
Well, I've been meaning to implement this into my own drawings. Basically, it's just adjusting the width of the lines in the line art when needed. That, and coloring the lines so that they are the same hue as the color inside the given lines, only darker. Maybe you already know what I'm talking about.