You can turn your $200 fee to write a press release into $2,000 to carry out an entire PR campaign simply by convincing clients to invest in campaigns, instead of individual assignments. Campaigns achieve better results and cost less in the long-term for clients, compared to individual assignments. And, of course, as the freelancer, you get paid much more for turning out a succession of assignments that assimilate a successful campaign.Here's how to multiply your writing sales by convincing.