Paul Giamatti, who portrayed a minor character in Saving Private Ryan, a paratrooper named Sergeant Hill, had some interesting insight in how Spielburg approached making that film.
(5:07 in)
"I've done other war things, but that was innovate what [Steven Spielberg] was doing in that movie. I don't know how many Steadicam operators there were at one time operating. It was not terribly structured, necessarily. It was very loosely blocked so that these guys were running around catching whatever they can almost like documentary filmmakers. And so they were all falling over and banging into each other. He didn't want it coordinated. It was a living scene. You weren't cutting all the time and stopping and resetting.
"I think I just fell because it was incredibly slippery and muddy. Everybody was falling all the time. I think from that, Spielberg starting developing this idea that the guy, his leg was messed up and he had a thing in his shoe, and he started just making that up. He would come over and give us a scenario and some lines. I didn't really have… there was no part, really. It was very, very sketched in. I didn't really have a character."