The most important is the packing and the way it's perfectly done : bomb proof isn't exaggerated. The courier is, hélas, to often a lottery, so put all the chances on your side with the best made package, the address typed and not written, a phone number clearly visible and the same paper inside the box. Think about the usual weather and make it "rainproof" as much as possible. Try to ship on Monday to avoid a long weekend in the overheated or underheated (depending the season) warehouses.
The shorter it's in the courier hands, the better it is.