"Silent Gladiators" talks a lot about the training and the mental component of Olympic freestyle wrestling, but is a little light on on-the-mat tactics.
I haven't really wrestled much folkstyle, but a few tactics that are common in freestyle:
1: Clean, well-executed shots with good setups are important. You don't see a lot of diving into a sprawl, which seems to happen in folkstyle matches. A bad shot is just too easy to counter for an exposure.
2: Scrambing happens a lot, but it is more controlled than in folkstyle because you have to keep your back up and your feet in bounds all the time. Freestyle wrestlers have great mat and body awareness.
3: Because of the short periods and tie-breaker rules, close matches can get pretty cerebral. Do you score early and sit on a 1-0 lead? Do you save your energy for a last second flurry? How comfortable are you clinching? And so on... yes, this can lead to stalling. Good freestylers are great at holding position while doing nothing- you can hand fight all day but if you start backing up, you can get hit with a "fleeing the hold" caution.
Hope that helps I suggest you look at some great freestyle matches and find some differences for yourself