The single most common thing we watch people get wrong is loading a unit like a lorry: everything in, door shut, done. Six weeks later they need the winter coats and the whole thing has to come out onto the corridor floor.
Leave a centre aisle
Load the two side walls first and keep a foot of clear floor down the middle. You lose a little capacity and you get back every single item without unpacking the unit.
Label the side, never the top
Once cartons are stacked three high you cannot read a lid. Write on two adjacent sides in marker, and number the boxes so you know at a glance whether one is missing.
Heavy low, light high, fragile last
Books and tools go on the floor. Bedding and lampshades go on top. Anything breakable goes in last, at eye height, where you will see it before you lean on it.
