I don't write a critique often but I'll go ahead and do my best for this one.
Now, I know that the rating looks bad but fear not! I will do my best to help and critique.
The drawing does look rather unappealing to the eyes and like it was done rather quickly. It looks a lot like some of my first anime/manga-esque drawings which were done a good 3 years ago at least.
You should look up some basic 'How to' draw manga artwork tutorials. There are plenty on DeviantArt and I can even link some to you if you'd like. That is a first if you are a beginner/unsure of what you can do.
You should try to define the head and chin more. It looks very uneven and it even appears as if one of the ears is missing. If it is the 3/4th view you are going for, then you should define the cheekbone more and move everything over slightly. SO the eye far from the camera would be slightly smaller (more compact/smaller width wise) than the one closest. Also, in 3/4th view you wouldn't be able to see normal human ears.
The eyes look somewhat uneven and very basic for manga/anime-esque style. My suggestion is to explore different styles/types of eyes and try to figure out which one you like and practice on drawing them so the eyes can seem to 'pop' out more. With Anime/manga drawings, the eyes should pop out more to the viewer as the eyes are "The Window to the Soul". Of course, you don't have to make overly huge and sparkly eyes however, you should give them a little more 'umph' than this. Also, try to give more definition to the lashes and even adding some that come out on female character instead of making the outline of the eyes seemingly just a line.
The neck is too long, it really shouldn't be that long. You have it more or less correct width wise, but length wise it is too long before it would seem the shoulders connect. Look at some reference photos of people (realistic or anime/manga styled) and see what the length of the neck is.
This is pretty minor, but the ear does have shape. No matter how hard it is to get those buggers right... It isn't just a simple line or two that connects to the head. It does come away from the head and have at least a minor shape to it. Don't worry or fret if this takes you a long time to learn, it took a while for me to learn that too (and I still am). Look up some tutorials on anime/manga heads and where to place the ears and small tips on how to draw them correctly.
The hair (and this relates back to the head a bit) seems like it is glued to the head. It is very flat at the top, suggesting that the skull itself is flat at the top which it isn't. Don't worry, it took me a while to learn this as well. The hair itself also looks very stagnant and flat with no actual definition to it. Remember that the hair (especially at the top) does come away from the scalp (slightly though) and follow the contours of the head. So when the head curves, the hair does as well. The hair curves (especially around the head) and this on its own can give its own bit of definition. As far as trying to give more definition to the rest of the hair (Such as the bangs and the main length) try more sweeping lines and light lines.
Also, especially when you are beginning, Guidelines are your best friend. They can help you correctly place where the eyes, hair, ears, etc. If you don't know what some basic guidelines are, then feel free to ask me to send you some or search around for some.
Even though the rating looks bad like I said in the beginning, I'm sure you will improve with time.