Occasionally callers will solicit strangers. When you do this, begin by doing a tiny bit of research on the donor. In most cases you won't need a full donor research report, a quick google search will do the trick. Especially important are employer/occupation, family information, and name pronunciation.
If you find yourself needing to establish rapport, quickly, there's nothing quite like asking for advice. As the old adage goes, "Ask for advice and you'll get money. Ask for money and you'll get advice".
If there's no prior connection to the donor, look for commonalities. Shared interests, experiences, and values can make any phone call warm.