Revolutionary War in Camden, S.C. (previous posts here and here), this helpful young lady in the American camp explained what a lady would wear in colonial times.
The first layer is a shift, which serves as slip during the day and nightgown at night. Her white shift shows at the sleeves. Next she wears stays (a corset) and petticoats of linen or wool.
Her outer layer is a carico jacket, an upper garment which is open at the front, revealing the petticoat. She could also wear a short gown or a bed jacket.
She ties an apron around her waist and tucks in a neckerchief to protect her skin from the sun and for modesty. Colonial women wore caps as a matter of course, but the straw hat she wears on top of it is optional.
Seventeenth century women didn't wear anything under their shifts. (Re-enactors, however, prefer modern underwear to a chilly November draft!)
For lots of details about what colonial Americans wore and how they lived, as well as simple patterns and instructions to make your own period clothing, I recommend Tidings from the 18th Century by Beth Gilgun.
If you're not very handy with needle and thread or don't have the time, vendors at re-enactments — like the lady with the blue straw hat — will be happy to sell you ready-made dresses, caps and other items.
Next week I'll return to the 21st century for bookish events in North Carolina and Pennsylvania. Fill out the "Follow by Email" box in the sidebar of this page to get posts delivered right to your inbox.