• Try to read your instructions from the viewpoint of someone completely new to your project: are there any potential ambiguities that you can clear up through the use of different language or explanation?
• Order your instructions or explanations in the order that you think the questions would arise. For example, you wouldn't necessarily explain a task interface before explaining the purpose of the task.
• Similarly, many assumptions that you may take for granted exist because you have the context to understand the purpose of the task. Providing a short paragraph explaining what you're doing and why can answer a lot of nuanced questions that you may not even expect.
• Detailed explanations are great, but it's also possible to dive into minutiae that can discourage people from reading further. An organizational approach of: Purpose -> Instructions -> Common Mistakes -> In-depth answers/Q&A is a good one.