Matt Gemmell on the classic question How do you get your ideas, or the relation between reading, writing, and the idea-flow:
The corresponding answer is usually something like “they just come to me”, but it’s a half-truth. We all know that, deep down. The reality is more prosaic: your outlook alters, such that everything is an idea. In the same way that a former spy can never fully switch off their vigilance, a writer’s imagination just becomes perpetually active. Reading is what makes it possible - you have to read in order to be able to write - but you have to write to actually activate this shift in perspective. It happens fast: within days. The problem isn’t ever finding ideas; it’s filtering them.
Reading is important, even if you are not a writer yourself. Finding time for reading long form –books, long articles, etc.– is crucial, even if it seems to be increasingly difficult.