There are many tried and true forms of marketing libraries today. Networking, emailing, calling, and requesting an audience with a department are all common practices. The key to successfully utilizing these practices in your liaison areas is persistence.
Graham, Jamie M.
"Successful Liaison Marketing Strategies for Library Instruction: The Proof is in the Pudding,"
The Southeastern Librarian: Vol. 56:
1, Article 4.
Available at: https://digitalcommons.kennesaw.edu/seln/vol56/iss1/4