Before you start buying items or fabric, consider what's already sitting in your closet. This is particularly the case for guys, but can also work for women as well.
Dress shirts and pants are a fine base for a man's costume. More casual shirts, such as collarless shirts, also often work, particularly if they have at least a partial set of buttons and have long sleeves.
Modern jackets can also sometimes work. Take a look at Victorian photos or illustrations, or watch a movie set in the Victorian period, and you'll find some good, quick reference points as to what looks the part. Men's coats and jackets really haven't changed all that much in 100 years.
Suspenders and vests are nice touches, if you have them.
Dress shoes are a good standby shoe. Work boots might work depending on the style of boot and type of character you're attempting to portray. A wide variety of fashion boots are also useable.
For women, long, flowing skirts are an excellent base, although you'll want to stay away from straight skirts.
Blouses made of lace usually skate by regardless of style.
A variety of jewelry is also appropriate. Stay away from items that appear to be made out of modern materials like plastic. Metallic items, antique-looking pieces, cameos, lockets, filigree and items bearing gems or faux gems often work splendidly.
If you're going to be wearing a long skirt, shoes aren't terribly important. If you're planning on having your shoes be visible, a fair number of dress shoes will work. Take a low, thick heel over a tall, stiletto heel. Avoid open-toed shoes and sandals. Fashion boots are another popular option, particularly ankle boots.
If you have a crinoline or hoop skirt (usually bought in conjunction with a prom dress or wedding dress) you can certainly make use of it, presuming your skirt can fit over it.
Wide, decorative belts of leather or leather-like material are an easy way of uniting blouse and skirt, as well as providing something from which to potentially dangle props.
If you have a spouse, you might search his or her closet as well. Some clothes gender bend well. Of course, having a spouse that is roughly your size helps wonders in this regard.
Read more: