To succeed at Salesforce as a technical writer, you'll need a driven work ethic, strong writing skills, and the ability and willingness to learn on the job. I came in with almost no technical knowledge about the profession, and barely even knew what it meant to be a Technical Writer, but that didn't seem to matter much. Salesforce truly wants you to walk away with more than you came with, so they're really not concerned with what you know going into the internship. As long as you're a dynamic learner and are open to critique, you'll thrive in their work environment. Also, you will work with XML and DITA at some point in the internship, regardless of what your specific project is, so by the end of the summer you'll have developed a firm grasp on the technical skills that come along with the job.