Ask the staff to stick a “Fragile” label on your baggage
It’s a known trick on the Internet: tell the staff at the counter that you have really fragile items in your suitcase, and it will get a special label along with promises that they’ll take particular care of it.
Don’t overstuff your suitcase
By their own confession, baggage handlers sometimes make a game out of it. “In the hold of the plane, we would throw the suitcases to each other from the belt to stacking them up. We throw them to each other as hard as we can. We don’t want to break the bags or cases, but you can imagine that it is not exactly beneficial to the bag.” Therefore, the heavier your bag, the more damage it would receive.