Just start posting in forums, web hosting related websites, and maybe even coupon sites such as retailmenot.com. International clients come from any venue you advertise in. Like romes has stated, getting local clients would definitely work also. There are many small businesses out there that do not have a website at all and convincing them to jump on the bandwagon would be beneficial for both of you.
On the other hand, you can always target a specific audience as stated by romes also. You can choose to market to Magento Shopping Cart users, Ruby on Rails developers, Blogging Enthusiasts, FFmpeg Hosting clients (if you have the capability to offer it), and many other fields of interest that users are looking for.