From scratch? Well that won't be an easy task to handle (at least for me to comment)... Well you can seriously benefit from these
anatomy refs. Anyway, Here we go!
- right shoulder needs to be shorten, doing this you'll also logically retrieve the real proportions of shoulder/arms/forearms
- right leg seems out of perspective (without ref I cant say more)
Overall, your result is encouraging, palette and contrast are carefully planned, we have a readable human. IMO all you'll have to do is correct anatomy flaws...
Bonne continuation!