You've certainly improved upon your technique for drawing! I'm extremely glad to see that you've kept your cute facial design style but have also vastly improved on your body design overall. As for the entirety of the piece itself, it's time to break it down!
So overall, I like the design style.The nurse uniform with the needle and clipboard. It really fits nicely and honestly you've given it a really nice sexy-flare to it with the black stockings. For the needle itself, I wouldn't of minded seeing something inside of it, as well as the part that when pressed down pushes the liquid out. Still, not being able to see inside of the needle gives it some level of mystery. Like "What's inside that needle?" is the first thing that comes to my mind when I look at this.
Making her twin-tailed was a nice way of showing off her youth, as her body type and clothing give more of an adult vibe. I'm especially liking what you did with the twin tails themselves. The hair ornament is especially cool, I really like the design and style of it. The medical cross on both of them needs a bit of tightening up, but I sort of like the whimsical nature of them not exactly being perfect.
The face is really where you've gotten a lot of improvement. Those eyes are seductively haunting. I light the level of light blue applied to the lower area and making the rest a bit darker. The level of blush applied fits nicely with the perspective of the character given, and her face looks well balanced and proportioned.
The overall body design looks great as well. Hands are nicely done, and nothing looks out of place for the gripping of the needle and the clipboard. I also like the inclusion of a long-sleeved undershirt. Generally, the traditional outfit is short sleeved and the artist goes for more skin on the arms and legs. Where as I really like this idea behind it. It sort of looks like she's got elbow pads on, based upon the line art, so I'm not sure if that's another shirt or something else entirely. The uniform itself is also rather cute. You can easily tell how the uniform is put on and the slit on both sides of the outfit offers for more mobility and less uncomfortable movement, so it's definitely well thought out. The shading and coloring on the uniform seem to look pretty spot on. My only real issue is when it comes to the breasts. Generally speaking, with most clothing the breasts don't exactly wrap around it, which is sort of the appearance that is given here. While it is a common approach that most artist in the anime-based community do, it is something that I did want to pinpoint in case you were interested.
I remember you previously mentioned frequently that you had trouble with backgrounds, but I think you picked a perfect choice for this one. The checkered board background works wonders for this. It fits with the coloring of the uniform and considering the pattern itself is uniform, I can't help but to find it a perfect fit. So much so that I would love to see a higher quality image used as a wallpaper background. Perhaps in the future? : D
Either way, I think this is a solid piece. It definitely shows a deal of progression that you've made and some very creative choices as an artist. Nicely done!
