My advice is to study the human body, by first learning realism you will effectivley be able to do other styles of art.
Ears, not elf ears, normally start where the bottom of the nose is to where the eyebrow is, can seem different depending on the angle your looking at.
For arms, upi either have the arms without muscle that is pretty 'flat' or 'smooth' wichever word works better, or the more muscular arm where you would see bulges where the muscle is, the bulge becomes bigger when the muscle is being flexed/used, and when its not its more relaxed.
The body isnt the most easiest thing to learn, though i find it much easier than eyes, noses, hands, feet, and for the moment rose petals.
I cant really explain how to do hair, but your hair isnt bad
sweatdrop In the second to last picture of the girl, it looks like you tried to draw the collar bone, simple as it seems, it is a bit tricky to learn, you dont really see it connect with your should, but it does go in that direction, try feeling your collar bone, seeing when it sticks out most, where it goes, how it goes ect.
her chest looks like its being puched up, i dont see any signs of a shirt or bra, so it shouldnt stick out as much as it does, the would be loosley hanging with no outside support. (hope this makes sense.)
I can tell you have gotten much better on the eyes though.
The last ones eyes are very well drawn
heart With layered clothing you may benefit from trying to make certain parts look like they are coming off the body a bit, an example picture since i dont think im explaining this to well

You can see with this persons shirt (even though technically they are leaning forward), but it shows how the clothes can come off the body. Not the best example but its better than nothing
sweatdrop and another thing for clothes they wrap around the body, this is a little different for baggy clothes were they just kind of sag
Hope this helps you,
heart and hope i didnt sound offensive or nothing
sweatdrop