...is never easy. How you go about it depends on your topic. It's a good idea to ask for personal help from a professor or librarian; they may recommend a specialized resource for your research. Here are some search tricks you can try:
You can limit your search in many news databases by document type to interview to search for this type of primary source.
Google Books offers free full-text access to many out-of-copyright e-books. This includes archival and primary source materials. The easiest way to search for these titles is to use the advanced search page and select full view.
Use the advanced search in One Search and search by author/contributor to find autobiographies/ memoirs/ photograph collections/ poetry (primary source) by musicians vs. searching the musician's name as a subject to find biographical information (secondary source). You may have to broaden your search to CSU collections if you are not coming up with many titles at our library. You can then request the title you need using CSU+.
Refine your search by subject to documentary