For my answer I am assuming your clients are small/medium businesses?
My idea: It will take some time and work, however what you could do is some 'proactive samples'. By this I mean the following;
Decide on a category of business where you think translation is important and the customer is likely to have money to pay you. Then do a small something for them for free e.g if they have a website then translate their about page for free and send it to them. Let them know that they can use that page as they like and if they wanted to do the whole site then it would cost ***.