I'm in south Florida, and cold calling has worked terribly for me. I'm going to be shadowing with a doc who knows my dad (he set this one up for me - thanks, Dad!). The only other shadowing I've gotten was from a huge regional group/chain practice I called. They put me through to their supervisor, who then got in touch with the docs and asked them. Two said "yes." This all happened the week before I'm applying (this week, I plan to submit on Tuesday), so I've basically been shadowing every day to get some hours before submitting. I will mention on my AMCAS that in will be ongoing. So I guess one of the more productive cold calling techniques would be to call big group practices, ask to speak with a supervisor, and then ask them if ANY of the docs would be willing to let you shadow. Don't give up calling; it's a very discouraging process, but it eventually happened for me - the week before I'm applying!