It depends which side of the business that I am promoting. For the machine shop side I do some cold calling, and if there is an account that I really want, I try to get a referral from a current customer. I have picked up several accounts because mechanics have changed employers and then recommend me. I have 1 customer who has a lot of connections. He has gotten me in to see the right guy, and just that quick I had the account. As has been said for so many years " its not what you know, its who you know". I had tried to see the right guy at least 6 times and got nowhere. Then, BAM, I'm there and they are treating me like a long lost cousin. Giving me a tour, introducing me to everyone. Of course I've had to keep up my end by doing quality work.
Another technique that I have used: anytime I buy parts, I ask who they use for machine service. Chat up the services that we perform.
On the motorcycle side of things, anytime I ride, I make sure to wear a company t shirt, have plenty of cards, and maybe some other little give-aways. Even a line card listing the brands we sell ans services we perform. This is much easier to promo because it is much more mainstream. I will also go out to events and rides to mingle and promote.
Hope this is helpful.
Mike