Primo, the library catalog, is one of the best tools you can use to search for books, articles, and media. Sometimes, however, the in-person serendipity of browsing through the print collection is what's called for. Use the outline below as a first step toward discovering things you didn't know you didn't know about.
GT 500 - 2370: Costume and fashion
GV 1580 - 1799.4: Dancing
PN 2053: Production and direction
PN 2061 - 2071: Acting
PN 2080: Monologues
PN 2085 - 2091: Stage management, light, scenery
TT 490 - 695: Fashion. Costume design
What about plays? Browsing for dramatic literature is harder, since it is interfiled with other literary forms and criticism. American plays are to be found between PS 700 and 3626, with writing after 2001 coming between PS 3600 and 3626. British plays may be found between PR 1803 and 6126. Shakespeare, for reference, is located between PR 2750 and PR 3112; more recent works have larger call numbers. Twenty-first century writing begins at PR 6100.