Try Interlibrary Loan (ILL)! With ILL, you can:
If all else fails, you can always try searching Google Books to see if you can access the partial or full text of the book you need!
Sometimes if the Library doesn't have the full text of an article, you can find it by searching for the article title in Google Scholar.
Actual physical browsing (in the stacks) can sometimes help you find what you didn't realize you needed. Begin browsing upstairs in the Circulating Collection (books you can take home) and on the main floor in the Reference Collection under the following Library of Congress call numbers:
N1-9165 Visual Arts (General)
NC1-1940 Drawing, Design, Illustration
NE1-3002 Print Media
NK1-9955 Decorative Arts, Applied Arts, Decoration and Ornament
NX1-820 Arts in General
NX654-694 Religious Arts