The U.S. Marine Corps has Ender's Game by Orson Scott Card on its recommended reading list for officers, saying that it offers "lessons in training methodology, leadership, and ethics as well."
For the wirework in the battle room, the actors trained for a month with individual Cirque du Soleil members so they could do the wire performances themselves.
Asa Butterfield, Hailee Steinfeld, and several cast members that portray Battle School cadets in the film went to Space Camp prior to filming to train for zero gravity sequences.
To achieve the effect of weightlessness for the actors and actresses in the battle room, two rigs were invented for this movie, used to capture zero gravity scenes. First was a lollipop arm, which is like a counter-balance offering a full range of motion. The second innovation was a "people crane." It's a contraption, sort of like the lollipop arm, but put on air pucks so that the effect is like you are floating around in the air.
Several props used in the film were created using 3D printers, including a model of Mazer Rackham's ship seen hanging in Ender's quarters.