The first picture is fine regards dressing within the limits of hijab, but a pop of colour somewhere - maybe her hijab or handbag, would have been nice. Gold or brass buttons on the coat would have broken up the black a bit too:
I really like the dress the girl is wearing, but I think it's obvious why this particular combination is a no-go. Full-length sleeves and a pair of black trousers underneath should sort it though:
The girl on the left's outfit I would wear, though with looser trousers maybe. The hijab is a not-so-obvious choice with that gorgeous trench, but I think it works really well.
The girl on the right scores top marks for uniqueness - how many times have you seen a fabric doll appliqued onto a skirt? But I really don't feel that a short skirt with long boots is enough for hijab. If it's going to look good, then the boots need to be tight - which obviously shows the shape of the legs. And loose boots just don't look good at all with knee-length skirts. That's apart from the problems when you sit/bend over/remove boots to pray...I just avoid it altogether...
More Turkish street style to come soon!