While I can't speak to the mechanics of the latest edition I can give some more general advice.
* Don't think in "roles", it's all just people trying to stay alive and get something done.
* Don't do D&D style dungeons, this isn't a resource management game and they aren't using boffer weapons.
* Get a handle, any handle, on iterative probability. It doesn't have to be perfect or mathy, just a rough understanding that three 30% chances is not like a 90% chance it's more like a 60% chance.
* Real tactics are real strong. Gamey tactics only work if everyone agrees that they work.
* Don't drop perfect stealth surprise rear attacks on the back line non-melee characters each and every time. It gets old fast.