Calling some company/person who you have never met can be terrifying. It's awkward, uncomfortable, and definitely out of almost everyone's comfort zone. The truth about it is that it CAN increase your business and WILL land you new clients. It may not happen in the first 10 calls, but you must be persistent.
I've heard some pretty astonishing statistics about photographer's. The average amount of income for a photographer is about $24,000 a year. Not that much if you are trying to support a family and own a home. The top ten percent of photographers earned about $49,000 a year on average, with about half of the professional photographers earning in the 17k to 34k range. MOST photographer's will give up trying within their first 3 years. Those who last a bit longer generally can make some good money and will become full-fledged professionals. The truth about these statistics, is that they are based on the majority of people who will not give the business their all. If you work very hard, are dedicated, and strive to make the best images possible, you can do very well and make much more than the average top 10%. On top of all this you will need to market your business. This is where cold calls come in as an important tool.
I've just started making more and more calls, and have already increased my business! For years I have shot off hundreds of cold e-mails which has been the basis for my survival and income. I highly recommend doing this along with cold calls. Before you grab the phone and start dialing, create a basic call script and practice it a few times while making sure that you don't sound like a robot or a voice recording. Start with an introduction, and then ask who you should speak with regarding the companies photography. You won't have to have pricing right away. When you start speaking with the right person, ask them if you can come in and show them your portfolio, or if they are out of state, if you can e-mail them with a link to your online portfolio. I built my portfolio as a book using Shutterfly.com.
Don't be nervous, because it's highly unlikely you will drive anybody away by doing this. It put's you at an advantage over other photographers and is not as common in this industry as many other marketing methods. Sometimes a little verbal communication is all it takes to have a company truly consider you.
Now that you know some statistics, and some basics for marketing, get out there and bring up the average!