The new edition of 40K presents a lot of options on how to set up a game. Of course we always had the option to play whatever kind of game we wanted, but having a number of options codified can make things easier (hey, let's pick one of these) but can also lead to confusion (what do you mean I can't use the same stratagem twice?) if players come with different expectations. You should always have "the conversation" before a game to get on the same page. Perhaps something like this will make the conversation easier.
++Warhammer 40K 8th edition pre-game checklist++Who’s playing?Where/When?What time do we need to end by?Do we need an extended break sometime in the middle (meal, etc.)?Will any player need to step away on a regular basis (smoke breaks, store owner to help customers, etc.)?Who’s playing what?Comfort level/experience of players? Does any player need help? Does anything in any army need to be explained?Is there a particular mission we are playing? (tournament test, custom narrative, special campaign mission, etc.?)If not, what type of mission do we want? (Open War cards, War Without End? Crucible of War, Eternal War, Maelstrom of War, other?)Battlezones?Night Fight? (p.252)Fire and Fury? (p.253)Psychic Maelstrom? (p.253)Planetstrike? (pp.254-7)Cities of Death? (pp.258-261)Stronghold Assault? (pp.262-265)Death from the Skies? (pp.266-269)Other?Points or Power Level? How many for each player?Must armies be Battle-Forged? Any restrictions on Detachments?(Matched Play style restrictions)Do armies need to allocate reinforcement points to summon daemons, etc.? (p214)Psychic Focus? (other than Smite, each psychic power only once per turn) (p.215)Strategic Discipline? (Same stratagem can only be used by same player once per phase. Does not apply to those not used during a phase such as before the battle begins or at the end of a battle round) (p215)Tactical Reserves? (At least half of an army’s units must be set up on the table. Any unit that has not arrived by the end of the third battle round counts as destroyed) (p215)Sudden Death? (p.215)Other Special Rules?Any special terrain?Is there anything we need to remember to track? (ex: for bonus tournament points or campaign effects)Do we have everything we need? (models, books, dice, tape measures, terrain, etc.)Any other questions/clarifications?GAME ON!