Build your network and nurture it. Then, after a while it will come along nicely. I run my business in the field of chemical properties, fluid phase equilibria, so really a niche market, but every year, I send a card to all my contacts in the field (100+ cards) and I try to write a personal note for each person. I takes time, but it now a kind of tradition I do not want to break (started for 2008). On the back of the card, I have a link to a summary of my year and what is coming next. 80% of my contracts are coming after such card.
Front of my 2015 card:
http://ceondo.com/media/files/img/2015-small.jpg
I use Moo to print the cards, quality is great and service excellent. This is a referral link, just remove the /share... if you do not want to follow the referral.