As I'm the only one in my department, I update all documents and write for multiple platforms and products. Grammar, Editing, and Proofreading helped a lot in my previous job. Technical Writing and Advanced Technical Writing also helped a lot. Senior Project-closest to real life. More Computer Science for everyone would help.
Theory is fine, but practical application is better.
They complement each other well. Exposure to as many Desktop Publishing and Help tools as possible. As everything changes so quickly, it's probably better to know how Winhelp.exe works, rather than any one tool. Getting specific Technical Specifications out of unorganized programmers. Interviewing subject-matter experts.