@syrup: Haha, I really love to draw buckles and straps, as for the hair...I just re-used the hair from my previous drawing to spare myself some time. Here is a link to how my base sketches look like BEFORE I put hair, clothes and all that stuff on them. LINK: Imgur
My work process: I always start with the circle for the head and then copy and paste a copy of the head under the original head and then I draw the shoulders, then I draw the breasts and work my way down to the legs. (The crotch is always near the lower end of the copy of the head) arms and hands are drawn after the body is finished. When that's done I start with the clothes or the hair on another layer, it depends which one I do first.
For poses I just use a reference or multiple references if I want to fuse them, I always draw a "nude" so I have an idea where the clothes should go and fold and stuff like that.
@syrup: I don't really do "rough sketches" unless I'm making comics, but then it's just to give myself an idea how the composition of the page is going to be. I did some fast sketching for the jacket on her back but I kept it somewhat clean and not too rough and made lines less thick with an eraser where needed because thin lines are easier to trace afterwards instead of thick lines.
@syrup: I think it's a bit of both, I mostly try to get a clear idea of what I want to draw in my mind before I draw. Drawing clothes just happens on the spot, as for poses I mostly just search for references on the web that look inetersting to me or that fit the characteristics of the character I want to draw or I try to find a reference of the pose I had in mind.