As someone working with software engineers for which English is not a first language I cannot emphasise the importance of this enough. I've spent the last year

As someone working with software engineers for which English is not a first language I cannot emphasise the importance of this enough. I've spent the last year or so consciously working on my writing and it's really paid off - especially given the current situation. Never assume anything about your audience's understanding. Break everything down into short, concise sentences. If you're attempting to get across a non-trivial concept avoid the temptation to use big words - even if you end up having to write more. When you're done take another pass and see if you can simplify things further.