After having written quite a few formal and informal documents and regularly explaining various topics, I've picked up on a few useful practices and things to be aware of.
There's a certain amount of words or time you have to grip your audience's attention. The attention span might differ depending on the medium, the individual and your choice of words.
Information might be understood to varying degrees, depending on the user's familiarity surrounding the topic. And ignorance (a lack of knowledge or information) is different from stupidity (a lack of good sense or judgement).
The combination between your audience's attention span and their understanding is what I call the communication window. Effectively any surplus words spent on the topic might end up being wasted.
Through hundreds of instances of feedback, or also often the lack thereof, and from analysing page analytics of web applications I've learned that it's important to write both concisely and in a way that's broadly easy to understand.
Apart from tailoring to the audience, the medium and the goal, to write concise text well you need to consider context, relevance and importance.
- Context so that the information can be correctly interpreted.
- Relevance to ensure information is useful.
- Importance, as some words might not need to be written at all.
Wikipedia Co-founder Jimmy Wales talks about relevance and undue weight in Lex Fridman Podcast #385
A great way to make information easy to understand is to provide a clear structure that is easy to follow. Use headings, lists, tables, diagrams, etc. to make the information easy to digest.