Freelance writing has become one of the more in-demand jobs both online and offline. While it may not make you rich overnight, writing for businesses, bloggers, marketers and online marketplaces may be enough to qualify as a part-time job and possibly even full-time for experienced writers who have the resources. Freelance writers can have a certain subject they write about and sell, or they can choose to be paid per word and take direction from their clients. Being knowledgeable about SEO (search engine optimization) content can prove to be one of the main keys to success as a freelance writer. On a related note, if you have experience as a journalist or a knack for writing, you can try selling articles to magazines and other publications.