This girl wears a long coat -almost the length of her dress. The fabric is probably a fine wool with rich shine. The coat’s armscyes are dropped unusually low, and the wide two-piece coat sleeves are bunched up around her arm, so this coat may be a hand-me-down or something meant to last several growing seasons. Although mostly obscured, two pairs of large buttons at the hem hint that the coat fastens with buttons and loops at the top. There are two barely-visible patch pockets; one is obscured by her hat, and the other is just below her left arm.
She wears a long scarf, fastened around her neck with a decorative pin. The ends of the scarf are fringed, and the scarfs appears to have dark edges, though it is unclear from the photograph exactly what makes the edges dark.
Her hat may be made of wool felt, based on the other cold-weather outerwear. I am unaware of other hat materials, so if you have any information please use the comment form below. The hat is trimmed outside with a dark bow tied at back, a ribband around the crown, and what is probably an ostrich plume on the side. The two long ribbons hanging down may be to tie the hat under her chin (I am guessing at this- correct me if you have other ideas).
The girl appears to be wearing a tasseled hairnet (see the light-colored tassel with dark head near her right ear). Her hair is center parted and probably bound in a low coil on the nape of her neck.
She wears a wide hoop, for her size, and her skirt hangs at least six inches off the ground. This silhouette is typical of adolescent girls of the period.