Writing Reveals What You Don't Know
The experience of sitting down to write a technical document and realising you don't actually understand the subject well enough — this is one of the most valuable things that can happen to you.
If you can't write it clearly, you don't understand it clearly. This isn't a writing problem. It's a thinking problem wearing a writing costume.
The inverse is also true: the act of writing forces clarity. You can't be vague on paper the way you can in your head. Fuzzy thinking becomes visible when you have to commit it to sentences.
The Formats That Matter Most
The design doc. Before building a non-trivial system, write a document: what problem are you solving, what constraints exist, what options did you consider, what did you choose and why? This is not bureaucracy. It's the thinking you'd have to do anyway, externalised where others can react to it.
The post-mortem. After an incident, write down what happened, why it happened, and what changes. The discipline of this is more valuable than the document. It trains you to look for systemic causes rather than blaming individuals or bad luck.
The weekly update. A short summary of what you did, what you're doing next, and what's blocked. Forces prioritisation. Creates a record. Keeps stakeholders informed without meetings.
On the Fear of Being Wrong in Writing
The biggest reason engineers don't write is the fear of being visibly wrong. Spoken words evaporate. Written words persist.
This is actually the point. Being wrong in writing is better than being wrong in silence because it can be corrected. A design doc with a wrong assumption gets a comment. The same wrong assumption unchallenged in someone's head becomes a system in production.
The Compounding Effect
Good writing is the highest-leverage skill most engineers neglect. A well-written design doc influences the work of everyone who reads it. A clear post-mortem prevents future incidents. A good technical blog post helps people you'll never meet.
Code runs on one machine at a time. Writing runs on as many minds as read it.
Start Small
You don't need to publish. The value of writing is in the thinking, not the audience. Start a private document. Write down what you're working on, what you understand, and what confuses you. Do this for a week.
At the end of the week, read it back. You'll be surprised what you notice.