TAKING PICTURES OF KIDS! kids are freaking tough man! I used to think "that can't be THAT hard"
but huh! even with my big fancy camera I only got maybe two decent shots of my friend's kids out of like 200!
Things I found helped - getting them outside so it's bright and your camera can take pictures faster - and also if you're letting them be active and walk around, make sure you are conscious of your background. So maybe have them play in front of a wooden fence or a background of just trees or something so no matter where they go or what they do the background will always be good.
Just out of curosity did you use the flash or does she naturally have a dark complexion? I asked that cuz in my early days my shots skin tones looked like that even with the built in flash. Things improved when I got a decent flash.
Try for a more neutral background next time or as suggested by Zirc outside in natural light is great.