Describe the work, not just the room
Explain what people do in the space, where the tasks take place and what is difficult about the existing lighting.
Capture the layout
A dimensioned sketch is a useful start. Include mounting heights, racks, machinery, work surfaces, doors and areas with daylight.
Understand the existing installation
Gather luminaire photographs, labels, quantities and switching arrangements where these can be collected safely. Do not open electrical equipment to obtain them.
Set the practical boundaries
Identify the location, operating hours, maintenance access, desired programme and any procurement requirements. A lighting professional can help develop the technical criteria.