OK two things.
First off, i realise you have much art which you would like to show, but we are very anti-double posting (and breaking rules in general), so what i suggest doing is posting one lot of images, waiting for a few comments, in which you can reply to, and then posting some more creations. I removed your quad'post, if you were wondering what happened to them.
Secondly, Your two sigs stretch down too far, click the link and correct the mistake. EDIT:I removed one of them.
Now, as to your images, your attention to detail is nice, well done on the shading in, do you have any of your own orignal characters?
The avatar of shik': His face is too squashed, i dispise image distortion like that, it really ruins what could be a good image. Same applys to the sig, if you were to correct this, then they would look fine. I do realise the text has to fit, but try to work around it.
You need to work more on your hands and faces, they look good but they are the wrong size compared to the body. Keep up drawing and it'll all make sense to you, if you really want to improve it's best to start by drawing real people, just go outside with a sketch book (a park or something) and draw people as fast as you can (no detail, just try to get the shapes and proportions right). Also draw more real people if you can. Apart from that just keep drawing.
Nice drawings, you could maybe clean up a bit of the black stain due to the erasing too many times, it is kinda raw if you just left it like that.
Not sure how much crit I'm supposed to give in this thread.
But one question: Do you sketch, like with guidelines and things? Or do you just draw and erase and draw and erase kind of thing?
1: - his cap is... strange.. ;P
- I think hand is too small
- I don't like places which are colored black, they looks...unaesthetically (what a word!! xD)
- am I blind or there isn't shading? ^^''
2: - I don't know why but I don't like her profile...
3: - he/she (??) is so stiff ( i don't know is it right word, I hate dictionars ;P)
1 - 6,5/10
2 - 8/10
3 - 7/10
Being honest, I don't like this arts ;P But they'll be better with time ^^ Uh, tired with writing in english ==''
i like the concept for the first and the third one, not to sure about the second one. in the first one it looks like the jacket is branching off of the arm, i dunno if its meant to be like that or what (don't actually know where the image is taken from) the folds in the clothing are good... but you can't actually see the turning movement in it all that well.... the eye and the hat is a little weird looking too.
though i said i didn't like the second one, i do like the hair. though i find it a little difficult to see due to the smudged marks made by either rubbing out or smudging of the lead (if you used a lead grade of HB or higher)
the third one is alright though it could use some shading, the eyes here look a little off as well
I think you should improve the body and the hand...
but still nice job ^_^