There are several ways to network. First of all social media is a powerful tool, be sure to have an active business page on Twitter, Facebook, LinkedIn, and other social media websites. Engage with your viewers on topics they are interested in. Be sure to use personal advertisements as well.
Also, word of mouth is a great way to get new clients. Be sure to give your repeat clients your business card and encourage them to tell their friends.
Lastly, get to know other designers online and offline. You can do a search for interior designers on Facebook and Twitter, as well as Google. You may even find networking groups that can give you, even more, ideas on how to find great clients.