Victorian costuming for women: caps and headresses.

_Graham's Magazine_, 1849. Wikipedia.
A woman old enough to be accepting gentlemen callers was expected to make sure that her hair was arranged attractively at all times, and if she couldn't manage that (like in the middle of the night, at breakfast, or when doing vigorous housework) then she was provided with hundreds of attractive cap styles so she could cover up her hair. Caps were also supposed to help keep the hair cleaner longer, in the same way that clothes absorb oil and sweat and help keep the skin cleaner. Women who were middle-aged or who had children were expected to wear some kind of cap almost everywhere, allowing them to just put their hair up neatly rather than elaborately, and allowing thinning and graying hair to be covered. You might keep this in mind when you wear your costume.

Of course, your hair should be parted in the middle and pinned up as smoothly as possible whether or not you wear a cap. Night caps, like the well-known "mob caps", were not worn outside the bedroom, or perhaps the breakfast room, in the Victorian era. Elderly or conservative ladies often wore caps under their bonnets when outside their own home. Depending on the formality of the occasion, a cap can have white lace, self-fabric ruffles, colored silk flowers, embroidery and ribbons decorating it. Simpler designs for the morning and at home, fancier for the evening or when expecting visitors. Day caps of the period covered the top of the head from ear to ear, and often had ruffles framing the face at the front edge, and ribbon bows over each ear and/or hanging down over the hair at the back. Visit the Cranford web page to see several cap styles for middle-aged and older women.

An easy “cheat” that results in a fairly period Victorian look, is to get a white lace-trimmed hanky, cut or fold it into a triangle, and bobby-pin it on top of your head, with the large point hanging down over the back of your head, and the fold or cut edge going across the top of your head in front of your ears. If you can sew or hot-glue, you can make a very simple cap by getting a piece of fine or semi-sheer white fabric that is at least 3 inches wide and at least 9 inches long, hem it (turn under the fabric edges and sew or glue in place), and glue or sew lengths of lace in overlapping horizontal lines on it, decorating it further with ribbon bows and/or pastel silk flowers over each ear and/or in the center.

Women doing war work in snoods, 1942. Wikipedia.
A popular headdress among modern Victorian costume wearers is called a "snood" and is like a hair net, but it is made out of colored crocheted yarn. The colored yarn snood did not exist during the 1850s and 1860s! It was a product of the 1940s and the practical styles that women wore while doing war work. The Victorian predecessor was called a hair net, or just a "net", and was black or "blonde" (natural unbleached silk), made from knotted silk thread. It was decorated with a line of ribbon bows or rosettes around its edge. For fancier occasions, a net could be made out of narrow velvet ribbon, with velvet ribbon bows and perhaps a tassel hanging off the back. The wearer's hair was pinned up as usual underneath, and the net was pinned in place, running across the top of the head from ear to ear about 2 to 3 inches back of the hairline, behind the ears, and following the hairline at the nape of the neck. The decorative ribbons on the net framed the face.

1855. Bancroft Library Collection.
A good option is to get a regular "lunch lady" hair net, in black or to match your hair, and glue or sew some bows -- coordinating with your dress -- along the edge. If you can't find a regular hair net you can wear a crocheted “snood”, but choose a black one, or match your hair color, rather than a bright color. Instead of decorating your net and bobby-pinning it to your hair, you can thread a satin ribbon through the edge of the net, and tie it in a bow on top of your head when you put it on. Whatever you choose, remember that the hair net is an ornament to the hair, not the thing that keeps your hair out of your face. Your hair should be pinned up inside, filling out the net at the back if you want, or not, and gelled or hair-sprayed so that it won't come loose and wisps of hair won't stick through the mesh. Don’t just pull it on like a shower cap and tuck your loose hair into the back! A net is generally worn without a bonnet, although it can be worn with a hat, especially a riding hat or a toque (pillbox shape with no brim).