You have a plethora of options here - some examples:

• Less is often more. Keep documentation short and focussed. Don’t try to explain the whole world.
• Prioritize: focus on important, interesting, special or risky topics, instead of striving for completeness.
• Document crosscutting concepts instead of many building blocks.
• Avoid too much detail: Use abstractions, especially in the building block view and runtime view.