Overall good understanding of anatomy, but her left leg (the one under her other leg) looks like it's sticking out from the middle of her body. I don't know if explaining myself well. >.< So I'll leave this here: [link] Look at the third one, starting from left. Since it's a similar pose, it'll be good reference.
Then the braids, they fall naturally. For the braids to be in the air like that, she'd have to be making a quick movement, but she's sitting, relaxing. If you wanted to show her braids, they could be falling over the shoulder or something like that.
And about the light source, on the head and torso it looks like the light source comes from the upper left corner, but the legs look like they're being illuminated almost from the front.
And well, like I said, I love how you colored it and the colors you choose, nice pin up without being inappropriate, and a little detail about composition: our eyes always tend to look at letters, they like to read, but even when you put that 'Free Kisses' poster, it doesn't subtract attention from the main figure.
Hope you can understand me, and that this is helpful.