My advice would be to work on your shading. You’re lacking some shadows in general. The placement of the hand and arm, would create shadows across the body and face, as well as the fingernails casting shadows over the hair and the jewellery casting light and shadow against the skin.
The hair lacks texture in the way that it has been merged, so perhaps add some more strand work in there, and don’t forget to add different shades of the main colours. Hair is made up of different colours within the main colour, so here you would use different greens, and darker shades to make up the black. Also it’s worth remembering the light source, so you remember where to darken the colour palette.
Also, the parting is a little peculiar, it isn’t connected, just sits in the middle it’s also quite thick and doesn’t look very natural.
The overall shape of the face is good, but could use some more contour and highlight. Create the right palette for the chosen skin tone, and then define the bone structure etc.
The eyes look sort of monocoloured. So try to add some lighter and darker tones in there to count for the natural pigment of the eye. Also add light reflection so that they don’t look flat.
When creating the clothes, try to add some texture, and shading to account for natural creases and the way that it hangs on the body.
Hopefully some of these things help. It’s still good, well done.