I think you guys are being too generic in your statements, thus not very helpful. And greeting new people very badly.
pixelPinoy, i think this piece has potential, but your techniques are lacking - normal for newbs
. Specifically, the things that bother me the most, from the more blatant to less, are:
Shading style - your shading is very messy. I couldn't even tell that was a robot until i looked at it for a while. Use the shading to indicate the volume of the shapes, and don't add unnecessary curves if they will break that feel. Also, you added unnecessary reflection "effects" on the robot which further confuse the eye. If you don't know how an object should look, try doing a smaller piece and/or look at real life examples, try to replicate them. Don't wing it, so it won't suck.
Lineart cleanliness - the lines, though clean (not many 2 pixel wide 'dirty' lines) look irregular in most places. If the robot is made of round shapes, it's good to convey that with lines that flow smoothly. You have a few lines here and there that "break" or don't flow that well.
Color choice - i don't understand why you chose to color the lines of the robot with two different colors, since they don't follow any logic nor add anything necessary - if anything, it further distracts the viewer. Also, the colors for the girls hair make it look very "noisy".
Lurk for a bit, check the threads, read the comments, take a look at the lineart thread, and you'll become much better, and in time, be able to address these issues with confidence. Hope you take these comments as an intention to help learning and improvement, not in a personal offense one (cause they're not).