Talk to your publisher. Let them know libraries do not compete with the book market; they stimulate it. Library lending promotes literacy, creativity, and innovation. Access to literature and knowledge through libraries must not be denied. Encourage them to make all of their titles available for sale to libraries.
You may also consider retaining the rights you need to allow for library lending by including language in your contracts similar to this:
Notwithstanding any terms or conditions to the contrary in any author agreement between Author and Publisher, Author shall retain the non-exclusive, irrevocable, royalty-free right to authorize the loaning of digital copies of Author's work, facilitated by libraries on a one-user-at-a-time basis.
...to other authors
Talk to your fellow authors. Ask them what's going on with their e-books at libraries. Tell them what you've learned.
...to the public
...on your website
Post this badge on your website or blog to show your support.
Copy and paste this html into your page to display the badge:
<a href="http://www.ala.org/transforminglibraries/a4le"><img alt="I support fair and equitable library access to ebooks and so should you." src="http://www.ala.org//transforminglibraries/sites/ala.org.transforminglibraries/files/content/a4le_badge.png"></a>