Look at the publisher's catalog . Not all catalogs have to be glossy, four-color publications, but they should include pictures of each book cover with information about the book and how to order it. Make sure the publisher can fulfill orders in four weeks or less. Look at other books the publisher has produced. Ask about the publisher's distribution system.
Many small presses sell most of their books through mail order and do quite well.
It's important, however, that the publisher has good mailing lists that will be relevant to your book. Go to a large bookstore and ask to order one of the publisher's books. If that bookstore can't find either the publisher or the distributor in its computer, it will have trouble ordering your title when it's published. Ask the publisher how your book will be marketed. Talk to the person who will be editing your book .