The KECK2/BICEP radio telescope project here, at Harvard, needed to do just that, and hired the American Repertory Theater crew to do the packing.
You can tell immediately that ART have been doing this, have passed down their best practices, and have been paying attention to how to do it right, for many years. You can also immediately tell that their team features clear communication and well-thought-out designs, by how easy it is to assemble their crates, and by the confirmatory labels that make mating parts match to each other.
The job they did was SO amazing, that I had to document their techniques.
Step 1: Packing Theory
The secrets are to have 1) a structurally sound box -- one that isn't going to crush or crumple, and that is well-supported and braced on the inside and 2) make sure the item you are packing is surrounded -- tightly packed -- with material, or generally otherwise constrained -- so that if the box is impacted, the object experiences little of the force. Packed, literally.
The ART crew did all of this with very high quality materials (e.g. no two-by-fours -- all milled lumber), the right types of materials (angle brackets when necessary, stiff foam when necessary), a clear minimum of excess packing material, very exact measurement and fitting tolerances, and a generally all-around incredibly high level of expertise.
Step 2: This Crate
The two compartments are separated by a plywood "floor" that lifts up. The floor has circular thumb-holes drilled out (with smooth walls, no splinters) allowing a human to lift the floor anytime. The floor is supported on its edges by a molding-like feature of 1x lumber screwed onto the wall of the crate, just below.
It slots down over the vertical brace lumber, and is cut to have enough room to slide by even at a ~15° angle -- which is exactly the amount of tolerance required.
Shown here in the first image is the crate, before packing, and its future lid (to be screwed on) leaning on the side.
Step 3: Braces
The bent nail is a retainer, and it is a tight-fit through the hinges that takes some "working" to pull out. It is highly unlikely to come undone in shipping, but is quick to insert and remove while packing the crate.
One of ART's true genius design novelties here was to not only encode which brace section went to which post with sharpie/lettering (e.g. Brace A, Brace B etc.), but by also using the hinge hardware in a puzzle-piece fashion, so that Brace A had two single-loop hinges designed to slot between double-loop hardware, Brace B had one of each kind, and Brace C had two double-loop hinges, slotting around single-loop hardware attached to the wall of the crate.
This ensured that even if the braces were cut to slightly different lengths, there was just no possibility of a lazy packer switching around the construction of the box.
Step 4: Documentation, Everywhere
Step 5: A Small Box for Hardware
We added a bill of the box's contents to the lid, in sharpie, when it was packed, so the receiving crew could check the contents against what they expected to find.
Step 6: Padding/Retention
The above-and-beyond winning technique, here, was a light coat of spray adhesive that stuck the foam to the alumiunm, and that ensured the foam would not work its way out from between the aluminum bars.
Step 7: Forkliftability
Step 8: Wrapping It Up
A final touch of American Repertory Theater genius? They left an entire roll of "This Way Up" arrow tape for labeling the box.