Start with the purpose
Write one sentence describing what the system provides to the aircraft. This prevents the study session from becoming a list of disconnected components.
Map energy and information
Identify the source of electrical, hydraulic, pneumatic or mechanical power. Follow how it is controlled, distributed and monitored. Note the systems that depend on it.
Learn major components
For each component, record its function, input, output and normal state. Do not begin with connector pins, torque values or removal steps.
Separate three layers
Layer one is general theory. Layer two is aircraft-family architecture. Layer three is the exact aircraft configuration and approved maintenance procedure. Keep those layers visibly separated in your notes.
Test understanding
Explain the system aloud, draw it from memory and answer simple questions: What starts it? What protects it? What indicates its condition? What other systems interact with it?