This could apply to any non-fiction, but for persuasive non-fiction, like opinion pieces, for example, resist the urge to dress up your writing in big, impressive words in a quest to sound more intellectual. In fact, try to make your point as simply and in an accessible a way as possible.
Notice I didn’t say “dumb it down.” No, by all means bring out as complicated of an issue as you like in your work. But, I am saying to make it accessible to as many people as possible by making sure not to obscure it any further behind your, no doubt, impressive vocabulary.
Here’s why: if your piece is going to land and be deeply heard and create any kind of change whatsoever, it’s going to have to be not just read, but also widely understood. In fact, several major new organizations specifically aim for below a 12th grade reading level in their opinion pages (i.e. where non-staff written opinion content goes)— a level at which a high school student or someone with less than a complete high school education could comprehend. And they do that because that’s the whole fucking point: if should be accessed and understood widely. Because for persuasive writing to work, everyone must be part of the conversation, not just those who had/have access to higher education and expansive vocabularies. Everyone.