Warhammer: Vermintide 2

• Hit your ping key (T by default) all the time to call out and mark specials, bosses, and items for team mates. If someone's playing Captain as Saltzpyre, tagged enemies will take more damage.
• Don't forget about using your career skills
• If you want to keep your teammates highlighted all the time, you need to change the visual setting for it from On to On (Always).
• Holy Sigmar, bless this ravaged body
• You and your team need to balance the ability to take out hordes, armored/tough enemies, and specials (bosses too, but less important) with your weapon loadouts. If everybody has high damage single target weapons, you'll get fucked by hordes. If everybody has close range weapons, specials will fuck you from a distance.
• Use chokepoints to funnel hordes and make them more manageable; open areas are generally a bad place to fight in.
• There are no melee only* or ranged only characters; use both, frequently. (*except maybe the Slayer class, though he can jump directly into trouble)
• Blocking is 360 degrees, though enemies hitting you from behind or the sides will drain more stamina
• Avoiding damage is key; mix in pushes with your attacks to keep from getting hit. If somebody is blocking for the team, remember that you may need to help them out by taking over blocking or doing immediate cleanup if they need to recharge their stamina.
• Strength potions affect all damage you do, including ranged attacks and bombs
• In parts of some levels (particularly near the end), enemies will keep coming out continuously and you should not hang around to fight
• Bosses: You can block or dodge most of their attacks, and they only focus on one person at a time. Keep this in mind and either focus on evading or attacking and position yourself accordingly.
• If you see one of those green tornadoes start to form, you can see a bit of a line that will lead to where the blightstormer is casting from (haven't verified this though)
• The elf is a magnet for pubbies who wander off and get fucked and then blame the team for not helping them in time when they get ganked. If you play the elf, it's possible you're one of them.
• Most levels have 3 tomes and 2 grimoires, both of which increase the quality of your loot after finishing the map. Tomes take up your health slot, but can be dropped to pick up health and picked back up. Grimoires will turn to dust if you drop them or if you die, and they reduce everybody's maximum hit points by a third, less if you're carrying a curse resist trinket.