There are numerous books and web-sites related to costume creation, pattern making and sewing.  Several classic patterning and costume history books are listed.  Internet searches using key words like basic sewing, how to make costume patterns, theatrical costuming, and costume history will provide additional avenues for research.  Additionally, many commercial sewing patterns can be found for both cosplay and costumes at local fabric stores or on-line. 

Many cosplay costumes reflect the design and style of Japanese clothing.  These texts are suggested references if you are interested in the history and development of garments in Japan.