Before you start your research, you might want to gather some background information first. It sounds weird, but browsing through encyclopedias and other reference sources will provide you with details regarding time periods, designers, fashion trends, alternate names and spellings, as well as additional background information on the broader time and place. Doing this work can help you focus your research.
Many reference materials are available in print; here are some great resources in both electronic and print formats:
These terms can be used in the library catalog, OneSearch, Google and any electronic resource.
Searches can be narrowed by adding names of countries or time periods
Searches can also focus on specific articles of clothing, for example:
If desired, you can search for fashion magazines by name (Godey's Lady's Book) or specific designers