Contributed by Coach Sones
This really is the best way to learn how to team fight as a team in my experience. We run this (15-20 mins) as a mic warmup before every match on game day.
Queue as 5 into ARAM. Everyone use their free reroll to have 10 total champs. Build the best team comp possible from the 10, and play the ARAM as teamfight practice. When not fighting, talk through how you are going to start teamfights, how enemy is going to start fights, how you win, how they win, what critical spells to look out for, etc. When fighting, focus on calling out targets, cooldowns on your critical spells (“I have my stun in 5”), cooldowns on enemy critical spells (“Ez used his E”), general fight strategy (“kite back” “focus frontline” etc).
Goal is to keep team comms as active as possible. If no one is talking about the game, you aren’t focused enough on trying to talk, as there is always something to talk about. If you make mechanical mistakes because you are on a new champion and focused on talking, that’s okay since you are trying to get comfortable talking and playing at the same time. With enough practice you will be able to win every single ARAM this way, since enemy teams are not trying this hard to win and are generally equal skill level.
Optional, especially good for the first few games: Review the replay as a team and discuss the ups and downs.