I am unable to find any tutorial to manipuation technique used here wondering if someone can help me out

What you're looking for is mostly Digital art, you need some artistic  talent, like Painting or drawing, check this video so you can see how the hair is done, tha back ground you Should already know since you're a  retoucher/Photoshop  user.
http://psd.tutsplus.com/tutorials/paint … ch_index=1

You do not need a to be a painter to do this but it does help as it has a lot of work with understanding light and artistic painting . It can be achieved with lots of practice . I mean years of practice . There is no one tutorial that is going to give you the answers . You would need to do lots of research and online tutorials and also trial and error to get that far with it . It cannot be achieved merely by using brushes , you would need to know how to draw in hair possibly and as you can see it is a whole different skirt etc etc ...Plus making the new background look believable even when it is a painterly type effect . Tones,colors,shadows,hair, etc are all to be learned when doing manipulations of this sort ...and you can always ask the artist themselves what exactly they did . I doubt they will give you a list but an idea .