If you want to master anything, a language for instance, you have to speak just as much as you hear and write. If you want to be a best-selling author, you’ll have to master the art of speaking to sell more books.
Consuming is the easy part. The hard part is making sense of a subject and teaching it to someone else. People also learn differently so you have to consider the audience. You may need to use an image for creative people and PowerPoint slides for more business-minded folks.
Learning and teaching are two different skills that take a ton of practice. Taken together, they offer the complete package.
Know what you teach. Teach what you know.