Overwatch
Team Comps
Overwatch is a matchup game. If your tank is losing space, a fourth DPS skin will not save the point. Swap with a purpose.
Ask what the fight is missing
Need a shield break? Need anti-dive? Need a peel? Name the problem, then pick the hero. Random one-tricks lose to the swap.
If two teammates already cover a job, pick the gap. Three snipers is a screenshot, not a plan.
Ult economy
Stacking two huge ults on a won fight is a waste. Track the enemy support ult. Hold yours for the next team fight if they still have it.
Voice is optional, pings are not
Ping the dive target. Ping the high ground. Silent teams still win if the pings are honest.
Players who like short recaps can find more in this handbook.