Hi yassein!
first of all the final fantasy models are quite advanced and itâs nice to see you striving for that quality but keep in mind that the people working on them have quite a bit of experience [doing worse things ;0] behind them
We all have to start at the beginning and will never start with a movie quality for sure unless weâre gods 
Good start on your model! The things that immediately jumped at me are the hard edges! This is an organic model and you can never see distinctive edges on a body, even though there are collar bones poking out and things like that⌠So Iâd suggest softening everything up quite a bit, which will make all the difference!
a great thing to do as well, I find, is to make a capture of your model, put it in photoshop - duplicate the layer and put it through the liquify toolâs hell - just start adjusting things while looking at anatomy and human references! look at the lines whatâs wrong, the proportions and such as if you were painting it! You can also draw a bit by picking the colours from the image itself⌠then just turn that layer on and off and compare to the original - it will help enormously to do that often!
As for the face - thatâs never easy so cheer up - youâll make it! The mouthâs width is from the middle of one eye to the middle of the other - usually - so you have to make yourâs wider for starters
Youâre also making the typical mistake every beginner does [ this is a been there, done that comment ;)], which is flattening the head since youâre using only front and side roto images!
look at your head from the bottom, or top and make sure that the nose and ears create almost a triangle - the cheeks are sloping towards the ears 
hope I could help at least a bit and hope you donât mind my honesty :)! Keep going 