Okay, uh, yes, the ratings do look really harsh - the ones I've given this deviation - but this piece of artwork isn't exactly nothing to be ashamed of, but is also a not very great piece to request critiques of. Moving on-- This picture is very basic from the looks of it and a good try being done in fifteen minutes. It's not particularly visually impressive, a good amount of detail would be necessary. The originality, of course, is very low due to the fact there are many like this out there. I've hit the word limit, so here you go!
Hello there! I heard that you would like to improve. Thus, I hope to give you some good advice to improve your work! ^^
One thing I'd like to say is the overall treatment of the medium itself. If you can get access to a scanner, I really suggest doing so. Taking a photo of your draw, like this looks like anyway, lowers the quality by making it full of shadows. Either way, with a scanner or not, another thing to do with a picture like this is to lighten it. It's pretty dark right now, looking greenish and bleh. If you can use a program like Microsoft Office Picture Manager or anything that has a brightness and contrast adjuster, I highly suggest it. By brightening your picture, it will look like a normal white background instead of this ugly dark greenish one. The contrast can also be used to darken your intended lines, since brightening will also lighten what you actually want to be dark. Toy with those to make a better quality picture.
As for the lines themselves, I suggest you darken them. A good technique is to draw very lightly when starting out. Experiment with light lines so your mistakes won;t be too hard to erase. When you're happy with what you have, then take that pencil and jam it down with GUSTO, man! Confidence! Show it off!
Ok, now onto the actual drawing itself. The face shape is looking a little wonky. Try looking at real faces while you draw, or even at yourself in a mirror. Mirrors can be really great for many things. Faces are very symmetrical, both sides are even. In your face here, take your hand and cover up the eyes, nose, and mouth so you can only see the head shape. Go on, really do it. You can see it kind of looks like it's facing front. Now do the opposite and cover up the head shape so you can only see the eyes, nose, and mouth. Now it looks like she's facing the left. ....Not good. To fix this, you'll need to choose a way for her to face. Forward or to the left?
Slightly side-facing characters can be tough. I highly suggest a reference for beginners. Look at yourself. Look at others. Look at pictures. First draw the head. Use lines and accurate proportions to make sure the face and the head actually line up. It takes practice. I highly suggest tutorials and looking at pictures to help you.
Here's tip for forward facing characters. I know manga style tends to ignore the nose. They do it minimally. But if you want to draw a forward facing character, I suggest you avoid the side-facing-nose-style they usually do. It'll look like the face is normal, facing you, except their nose is horribly broken to the side! ^^ I highly suggest actually drawing the nose. Look up pictures if you must, or else look at yourself. Even a minimalist nose is fine, such as only drawing the bottom part of the nose. A forward facing nose is part of a forward facing face. ^^ Manga is a lovely style, but I find it too bad when some people claim "But it's the style!" and limit themselves by only drawing it one way when they could be learning to draw more realistically. Just a thought!
I also suggest that the shape of the eyes might be improved if you finished drawing the oval shape rather than left it open. Fill it in, man! Make it look real. Add the upper and lower lids to them. Add some eyelashes. Pretty pretty eyes!
Also, the hair. Really beautiful manga involves detailed hair. When you get into animation, things are often simplified because drawing hundreds and hundreds of pictures and streaming them together is what animation is about. It MUST be simple or else it would be incredibly difficult. But you have the freedom to make lovely detailed hair. So instead of doing big chunks of hair, make it a bit more pretty and real. Look at pictures of hair and your own hair. Use quick lines, light strokes. See how it moves and flows and draw it. Are your bangs chunks like they are in this picture? Nope! Adding shading to it is also important to make it look real, but I'll get to that in a second.
Shading is another thing. Shading makes pictures awesome. It's like coloring, only... not. Anyway, shading is what makes lines turn into real looking cool artwork. Shading is what makes hair look real and pretty. Learn to shade and it'll vastly improve your art. To do so, think about where you want the lift to come from. For example, in front and above is common. Then shade where darkness would be. For example, under the nose, under the chin, under the brow. Shade in the hair, adding highlights where the light would be brightest. It'll make it look shiny! ^^ This knowledge comes with time and lots and lots of practice. Look in a mirror and see the lights on your own face. ^^
Overall advice: Mirrors, man. You may look silly doing it but it sure works. Use it for any complicated poses, any weird facial expressions, any lighting issues. Look at yourself. Also, look ta pictures. Do not be afraid to use a tutorial! Or just look at pictures and copy them (direct copying and posting is theft, but copying in private for your own practice and then scraping is alright.) You will find which techniques you like best. You WILL improve. ^^ So go, man! Google image search! ^^
I agree with the critiques, and once you sort out the proportions (which are my biggest downfall) and the placement of the features you should work on using the pen/pencil to emphasise certain areas and provide a bit more depth to the image. And then you can work on how to suggest personality with the features, expressions etc. Don’t forget, with practice comes great responsibility!! Um…that’s not quite what I meant…