I was recently with the sales team of a multinational software company to discuss online profile and making the most of their outbound sales efforts. 

The company use a technique called Basho (details and example below) that garnishes a high response rate, mainly due to the highly relevant message.

That said, if an individual is to respond they are likely to do their own homework on you. Most probably heading over to LinkedIn or search a company page for a demonstration of your expertise. 

In addition to the Basho technique I would encourage an up to date hub of relevant content relating to the topic you sell. This will separate you even further from the competition and backup your email with credible information.