Most people assume they know what they think, and that writing is just putting it down. Try it and you find out otherwise. A thought that felt clear in your head often turns out to have been a feeling of clearness. Writing is where you find out which one you had.

Compare these two sentences about the same subject:

Not yet a thoughtPhones have had a big impact on teenagers in many ways.

A thoughtTeenagers who keep their phones in their bedrooms at night sleep less than those who don’t.

The first sentence can’t be wrong, because it doesn’t say anything. What impact? Which ways? The writer hasn’t decided, so the reader can’t either. The second sentence names who, what, and what happens. You could check it. You could disagree with it. That is what makes it a thought.

Unfinished thinking leaves marks on the page. Watch for words that postpone a decision: impact, aspects, things, in many ways, it could be argued that. Watch for sentences that could be about almost anything. When you find one in your own writing, the fix is not a better word. The fix is to go back and decide what you mean.

If you can’t write it plainly, you haven’t finished thinking it.