Take everything out of the trunk and sort it into three groups: things you keep in the car, things you need for this trip, and things that can stay home.
Give the everyday items a place
A collapsible organizer can hold reusable shopping bags, a small towel, and other light essentials. Check the organizer footprint against your cargo floor and any storage panels you need to open.
Pack by when you will use it
Keep lunch, layers, or a change of shoes where you can reach them first. Put heavier items low and follow your vehicle manual for securing loads. Check that the cargo cover and hatch can close freely.
Leave room for the return trip
Bring an empty carry bag for damp gear or items you pick up along the way. When you get home, unpack what you added and reset the trunk for the week.