You can use paid advertising, free advertising, social media, online directories and a variety of other techniques to spread the word about your business.
Work on your own website.
Websites are important for any business to have as the Internet continues to pull in consumers in nearly every industry, but since websites are your business, your company definitely needs one. How you structure your website is up to you, but you should have a clear focus on what your skill is while providing the information potential customers need. Your website doesn't have to include your rates, but it should include your services, examples of previous work, contact information, and supporting educational information such as if you attended a web design degree program of any kind.
Pay for online advertising.
You could ad listings on high-traffic websites, or do a pay-per-click campaign with the large search engines. Pay for listings in business directories for web designers.
Become active in social media and in other online communities.
These are places you may find your customers. Facebook, Twitter, FourSquare, and other social networking websites give you another avenue to connect to both current and prospective clients while also giving them a way to connect with and learn about you before, during, and after the sale. Become active in places where you know your target market is and in industry-related communities to establish yourself as an expert.
Focus on search engine optimization (SEO).
Let the search engines do some of the work for you naturally at all hours of the day. If you are not familiar with SEO, you can either research and try your hand at it or hire someone to help you. Clients want to know their website is going to be seen, so if you can offer SEO services to your customers, then you have more value.