i can see you tried to do a kind of realism picture. the thing that pushes me to that conclusion is the way you drew the nose.
if you did try to draw realism. i would suggest to start with pencil.
and buy these books( i swear they're like a bible to me and not very expensive):
-Bridgman's Life Drawing(the book is green)
-An Atlas of Anatomy for Artists by Fritz Schider (the book is blue)
-George B. Bridgman Construction Anatomy (the book is orange)
they vary between 6$-12$ american.
but if you were trying to draw anime...i do not suggest buying how to draw anime books *twitch twitch* What a waste of money....trust me!
i just have my animation books. and of course....the books that i mention on the top...those help too still with anime. a bit less though, cauz anime is weirdly proportioned...but it still does help.
as for your drawing itself. it's a nice try to draw sailor moon. noses are hard to draw....i know, it's the thing i have the most difficulty to do.
i don't know what exactly to comment on...but i can give you some cc's to help you improve if you want.(you can just ignore the bottom part if you don't want to hear it)
sweatdrop the head should be smaller to match the body portion. the nose is too large, try making smaller. the nose should end at the end of the bottom of the ear. the ear should be higher, the top of the ear should be at the same level as the eyes. the eyes are at the right level. the top of the head shoul be higher. the bun that's on top of her head should be more on the side.
this is the part where i'm going to include the books that i suggested. The skull... on a 3/4 view you can see the back of the head. that part is missing from your drawing.
the neck shouldn't be on an angle. it should come straight down. the torso is too thin. the lenght of her upper arm is too short. the elbow should go down to the pelvis.
i know the last line might sound ridiculous, but if you stand up and put your arms against you on each side of your body, you'll see what i mean.
don't take my cc's as an attack against you...cauz it's not. from you personnally, you're really nice and i wouldn't want to attack you EVER!!!
(sorry, sometimes people freak at me when i do this)
but generally, it's a good sketch.
wink