Another big one: Thank you audience :) If they're taking the time to read, they're invested, and interested. :)
Don't patronise with your writing, and my favorite, definitely know your audience. You wouldn't write a review of a kids video games with a university level vocabulary, unless you were planning on writing satire. :D
Yeah. So right. The last one is difficult on a multinational platform. You don't want to speak too simply so that it seems patronising, but you want people who's first language is different to yours to be able to easily understand it. I have had to deal with that with my husband as well, English is his second language.
It is a tough balance. I once had a editor tell me to dumb my content down for the audience, but it was a review for a complex strategy game, with an audience of 30+ educated adults.
Very difficult balance.
It is hard when condescending doesn't come naturally. I hate being talked down to, so I don't like doing it to others without giving them the benefit of the doubt. But then once I did want to dumb a speech down for a certain adult audience and my colleague talked me out of it. Later I had some members of the audience saying it went over their heads. Live and learn I suppose.