The Curse of Knowledge describes the cognitive bias or limitation that makes it very difficult for humans to imagine what it would be like not to possess a piece of information, and hence to properly put themselves in the shoes of somebody with less knowledge than them.
The first, and most important, is to overcommunicate. What exactly is meant by overcommunicating? To me, it is two things: (1) repeat your key messages a lot more often than seems reasonable or comfortable; and (2) when in doubt about whether your audience has a particular piece of important context, always err on the side of providing that context.
Overcommunication may seem inefficient but when it comes to communication, robustness is far more important than efficiency. Remember that the costs are asymmetric: communicate too much and you pay the cost of small amounts of wasted time, but communicate too little and it could lead to major disasters.