You can give best and attractive packages to your existing clients for more references and also advertise your Working profile with some social media outlets.

You can create your own fb page and promote your work there. You can offer discount and other attractive schemes so it look useful and interesting to the reader.

Since you are a graphic designer, promoting your business via social media outlets can be a big help. You can use Instagram, pinterest, facebook, twitter.. there are a lot. Another thing about social media is that, it is crowded with millions of potential customers so there are more chances of getting better responses.

Try to launch you services on here on WF... and some other similar forum like digitalpointforum, BHW and wicked fire etc

I think a good way for you will be taking advantage of social networks, which will help you to promote your work. Twitter, Facebook, Google + and YouTube can be the good platforms for you.