I am in a services business doing high-end business development consulting.  The two points you mention that I have used and that work extremely well is cold calling and giving away something for free. In my service, I would never have thought that someone would pay for a consultant through cold calling but I have 2 highly lucrative clients that I have obtained this way. I also have 2 new clients that are coming on board this month. I am full now so I hope to bring on some help. 

   The other idea you pose that resonates with my business is tied to the first (cold calling), and that is giving something away for free. In my instance, I was able to look deeply at their capabilities and market, and then I provided 2-3 top prospects that they should go after and why.  This provided them with actionable intelligence that they were able to put to use immediately. I hope this helps anyone looking to do consulting or promote their services business.