Journaling/blogging is also a good practice. I write for my own sake (I don't share it out, in general) but I write as if for an imagined audience made up of people I know in real life. If the topic is technical, it might be some classmates or colleagues, other topics I have other people in mind.

Occasionally I share out what I've written, but directly not published on a blog. Presently, I'm doing some demos for work training sessions (sort of a rebalancing effort, we have some very skilled and knowledgeable people, but the knowledge isn't evenly distributed and we have some very new people to programming). So some of the things I've written in the past are becoming relevant, I'm retooling what I wrote (actually it's a full-blown rewrite at this point) to target this specific group and make examples more suited to this office than prior offices (programming is programming, except it's not, motivating examples should be relevant to the audience).