erik already told you the basic mistakes you do
whether you stick to manga-style or real ..whatever ...I think everyone has their own opinion on this...I started with manga too and than my style became more and more natural
BUT that's not an excuse for anatomical -mistakes!!
if you want to stick with manga than here some tips:
find a mangaka who is GOOD or even a GOD ( I refere to mangakas like oh great, obata aka tenjo tenge, air gear, death note etc etc. ) (NOT oda aka one piece who's anatomy is TOTALY off )
try to copy them and while copying, try to UNDERSTAND why he/she draws it this way and not different. if you don't get it, try to do the pose yourself in front of a mirror
for faces: find a mangaka who's faces you like and copy them as well...also try different emotions but only when you get the face PROPORTIONS
when you go for realistic humans (which is a lot harder because you easily get sidetracked by details like muscles, shadows and so on ) use books, internet or other references
also go for fast sketches, and set time limits like 5 minutes
this way you won't get sidetracked too easily because you don't have the time for details
tip: start with the basic structure of the human body (like a manikin ) draw a circle wherever the human body has an ariculation
than go for the outlines, this way you prevent basic mistakes or it's easier to correct them
I tried to show you with a few pictures I took while overdrawing your wip
but first: try to use easier positions first...sorry to say that but you can't use foreshortenings because you don't understand dimensions yet
you figures also lack dynamic, they look too stiff
here's your version:
FIRST THING I DID is, to draw the basic anatomy, I already corrected a few mistakes you did and added a bit dynamic....
as you can see this position is unnormal...try this position yourself and you see it's pretty hard to keep your balance (I didn't try it but i'm sure you'd fall over lol )
SECOND I drew the outlines and corrected the unreal position your character is in:
I shortened the leg and let him bow a little bit, also added dynamic
looks a lot better, doesn't it??
it doesn't give the impression that it's completely wrong ( yeah I know I still did mistakes but it was just a fast 2 minute correction to show you the basics lol )
well I hope that helps a little bit, good luck with it ^^
sorry for my bad english lol, I'm not a native speaker and way too lazy to read it once more lol