Start with the window
Light is strongest close to the glass and usually falls quickly across the room. Begin by noticing where direct sun lands in the morning and afternoon.
Watch the leaves
Plants that receive too little light often stretch toward a window, while sudden harsh sunshine can damage leaves adapted to shade. Change positions gradually.
Use a simple record
Write down the window direction and approximate hours of direct sun. Check new growth after a few weeks before making another adjustment.
Try a paper shadow test
Hold a sheet of paper beside the plant at midday. A distinct shadow suggests direct light; a soft one suggests diffused light. Repeat on another day before drawing conclusions.