I (my software

) counted a lot of colours: are you keeping a differente subpalette for each girl and her clothes, so to change them separate?
if it is so, ok, otherwise you could think using much less colours, like around 10 for the skin-tones, another 10 for hair, between 10 and 15 for the clothes and another 10-15 for the background. reducing much more the count, even if it is not a concern for you to keep the colour count low, it will give a much more sense of clean-ness to the piece, and you will feel more in control of what is going on there.
Another thing about colours, but not only: your colours do not spread enough in the whole range, you are using only a small part of the light ones, in a sunny day as the one you are painting shadows would be more strong, so punt in your palette also dark shades and use them (add strong shadows to the girls).
A third critique is that things in the far distance loose detail, so you should use less saturate colors for the mountains, and on the converse a more crisp palette for the grass on the foreground.
About shapes, you could use some reference to draw the clouds, 'cause now they are drawn in an automatic "childish" way (don't mean to be offensive, if you are used to non-pixel drawing, you should know that drawing in an automatic and childis way is a big BIG problem that all artist have when they start, and sometimes arises back after years even for skilled people...).
Keep going, you are improoving.