Isaac- When I ran my own consultancy, I specialized in creating marketing strategies for municipal governments. My best method for gaining contracts was developing relationships with key people who were connected in the industry. Some of my most profitable work came from word-of-mouth references from friends who heard that a city was looking for someone to hire for marketing plan development, newsletter design, or even a website.
Other than that, it takes a lot of hard work, and much of that includes submitting RFPs to organizations that are going to receive many proposals. The key is finding the way to make your firm stand out above the others and get in the door for an interview.
Best wishes to you!