Painting by Robert Lefèvre. Circa 1810 (Wikimedia Commons)
In the late 18th century, hairstyles were dramatic. The higher the better. People wore wigs or powdered their hair and often added adornments such as feathers, flowers, ribbons, and fanciful hats. Hair styling went through a dramatic change in the Regency. Under the influence of Neoclassicism, hair styles became simple and modest as ladies tried to achieve the look of the Ancient Greek & Roman goddesses.
Hair was often swept up and worn in a bun or braided and pinned up. If a woman wore her hair long, it was usually not worn lose but put in a ponytail or twist and worn to one side. Curls were very popular during this period, so many women would have to artificially curl their hair to achieve the perfect look.
Here are a few wonderful resources that discuss Regency hairstyles in detail.
Jane Austen's World has a great article showing many images of Greco-Roman hairstyles and their Regency adaptations. http://janeaustensworld.wordpress.com/2009/11/07/regency-hairstyles-and-their-accessories/
Mother Earth News shows how to curl your hair using curling papers, which was a popular method during the Regency (curling irons weren't as common as they are today). Women would apply a pomade and then use the curling papers to create the ringlets you often see in portraits and Jane Austen films. http://www.motherearthnews.com/do-it-yourself/curling-hair-zmaz71ndzgoe.aspx
Rapunzel's Resource, a website devoted to hairstyles for women with long hair, has fun tutorials showing how to re-create the hairstyles from Emma (she includes styles from the Kate Beckinsale, Romola Garai, and Gwyneth Paltrow films). http://rapunzelsresource.wordpress.com/?s=Emma
Note: posts usually include biblical quotes and religious references.
Jane Austen Today offers a 9 minute video tutorial on how to create an "up do" in Regency style. http://janitesonthejames.blogspot.com/2010/03/how-to-make-regency-outfit-regency.html
Timely Tresses offers patterns and materials to make bonnets suitable for Regency and Victorian ladies. They also have a page where you can order fashion plates to see what the gowns and hair styles of the period were like. (You can preview some of the plates directly on the website)
Main Page: http://www.timelytresses.com/
Fashion Plates: http://www.timelytresses.com/fashionplates/fashionplatebooks1800-1839.html
What is your favorite hairstyle for long hair?