Should I send an introductory email in the first instance, and then follow up with a phone call?
or place a cold call to the relevant person, or just turn up and leave a sample product? Any advice would be greatly appreciated.
More info required please. What kind of business? What kind of product or service? What kind of prospect do you want to attract?
Different industries have different accepted ways of making cold calls. However, all are based on making a compelling case for why the "call" is worthwhile. Your strategy will dictate what kind of tactic should be used.