The document outlines 7 things the author wishes someone had told him earlier in his programming career. They are to learn from everything, find someone smarter to mentor you, log everything for troubleshooting, test everything thoroughly, understand that as developers you provide customer service, there are two paths of development - innovation and stabilization, and to do something different occasionally to avoid burnout. The author shares this advice from his experience as a 20-year programmer and encourages others to pass on knowledge by mentoring others.