For taking better pictures of your drawings, go outside in the middle of the day when it's sunny and lay the drawing on some clean pavement, and take a picture of it there (being careful not to let your shadow fall over the picture). You'll get much better lighting that way, which will make it far easier to adjust the look of it in Photoshop. Once you're in Photoshop, along with Brightness/Contrast, try messing with Levels (Image>Adjustments>Levels) and also Hue/Saturation (Image>Adjustments>Hue/Saturation). A lot of the time, pictures will end up with a yellowish or other kind of color tint to them, so using Hue/Sat to desaturate that color from the image often helps it look better. Desaturation is easier with black and white drawings of course, but it can be used to desaturate certain colors, or it can be used on a selected area of the drawing only.
As far as critique goes, I was reminded of some tutorials Puncia had posted for someone else not long ago:
Awesome sauce.
Starting with the human form...
From what I see, the eyes seem a little flat and painted on, as well as a tiny bit out of place.
http://image.misterart.com/grouppix/528x352/3000/g3094.jpg
If you look here, you can see that the eye won't reach all the way to the edge, unless the head is in a total profile view. I think you should start there by defining brow muscle, eyelid tissue and cheekbone. Note how the eyelids in this picture are thick and have a 3D structure so they don't look like thin plastic stretched over the eye.
http://www.starwars.com/img/kids/do/draw/f20090622/maraeyetutorial.jpg
Will show how you can easily draw simple yet realistic eyes, giving the eye shape and form, eyelid folds and anatomy. But notice how this isn't as realistic as the first image.
http://psd.tutsplus.com/tutorials/drawing/photoshop-portrait/
Will provide a great and easy way to understand how to shadow an eye (and face) and understand how it works.
http://s1.hubimg.com/u/1005064_f520.jpg
And do remember that changing the angle also changes the shape.
I think your faces are the things that could use the most work. They aren't bad, but there's no real depth to them or anything. Sakura's eyes are too large for her head, and aren't shaped very realistically.
You also need to work on hands, and I get the feeling that you try to hide them from view to avoid drawing them when possible, which is never going to help you get better. There's about a million and a half hand tutorials out there, just type "how to draw hands" into Google or DeviantArt. Here's a random one I picked off DA:
http://fav.me/d3key45You need to work on your coloring and shading methods. Right now, the areas of grey/color look uneven, bumpy, and just overall look like you just scribbled everything in. Try using the full side of your pencil tips instead of the tip when filling in large areas, and press harder against the paper. I'd also invest in a
paper blending stump because they are super awesome and work like magic at blending. You can find them at just about any art or craft store, and in various sizes.
It's difficult for me to say much about the Fear drawing because there's not a whole lot to it. Chibis are hard to critique since they're usually so simplified that I can't tell if certain things are style choices or really do need improvement. One thing I notice though is that the hair looks really clumpy and kind of more like a helmet or something rather than hair. Looking through some of your other drawings on FA, I can see others have the same issue. Your Sakura drawing is far better in that respect; stray strands of hair and a flowing movement can go a long way into making hair look real, or at the very least, more like hair. Even if you're going for the anime style thing, there's ways to make it look light and flowy:
http://27.media.tumblr.com/tumblr_kvim7kim4h1qzhp2mo1_500.jpgThat's about all I have for you. I hope it's of use.
