Instructions
Do your research. Pick up a book like The Ultimate Barbie Doll book, which is available online and at some retail book stores. The book contains information on each Barbie doll and Barbie's friends, including Skipper from the 1980s. Descriptions are included as well as photos, model numbers and even estimated values. Or, check out something like a Teen Skipper web site, located in the Resources section. Click on one of the Skipper photographs for more information about each type.
Look on a legitimate selling web site that sells nostalgic goods like ebay or Amazon. Type into the search category "1980s Skipper" or "Skipper doll" and read through the different choices. If you have an exact description, type that in to find something more specific.
Browse around your local thrift stores or antique toy stores. Sometimes these types of stores will have just what you are looking for. Call the stores ahead of time and ask if they have these types of dolls or a specific Skipper doll from the 1980s.