Better still is to have a discussion with your players before you start about what kind of game everyone wants to play. To me this is one of the most important steps of setting up a game, because it makes sure that everyone is expecting the same thing.
The most important question to ask is if your expecting a Pink Mohawk or Black Trenchcoat/Mirrored Shades style of game. Both styles of game have greatly different expectations and focuses... if you have a group of players split between game types, or worse yet a GM/player split on this things will be problematic. If you're playing pregen content like the Missions, you'll be naturally leaning towards a Pink Mohawk style of game.
Another important discussion is danger level. If players dont feel at risk, they'll have little to invest them in the game, conversely if every grunt fights at maximum effectiveness then games could feel like an unfair slog (Unless your players want that!). For me I have what I call a Set Battle system, basically the bigger the fight, thr less punches I pull.
Typical Battle: Basically any battle dominated by Grunts or generic NPCs. Sure they might use the odd bit of edge here and there, but these are fights the players are expected to win anyway, no real sense is dragging it out.
Important Battle: These are battles that the story plot revolves around. Fighting named NPCs or moderately dangerous critters. You'll want to make the characters work for this, perhaps not pull every dirty trick the character can, but certainly make use of their abilities.
Set Battle: Bug Spirits, Vampires, Blood/Toxic Mages, Shedim, Major NPCs... and if course, Dragons. The players find themselves up against something that goes bump in the night in a big way, this could be a clymactic battle of a campaign, or the designer of the pregen content just decided to be a prick. Either way, the players are in for a fight for their lives, they're up against something that can kill a runner, or even an entire team of them... and they're going to try to. Here you need to be a little careful, don't pull your punches, but at the same time don't totally overwhelm them with an irrisistible TPK (unless of course everyonr wants to start afresh and wants theit characters to go out with a bang). One thing I would say about this, remember the rule of cool, of some player comes up with some crazy plan to get everyone out with their hoops intact, let it play out.
