Matt's thoughts in response to a Reddit post on team fighting in Heroes of the Storm.
Every other decision you make falls under this rule. Should you back out? Who should you CC? Who to focus? Whoever is going to kill you RIGHT now. Not dying is the most important thing in a MOBA, especially once you get to end game where a death can put you in time out for almost a minute. Sometimes you may need to take risks to protect more of your team [take "Don't die" to mean "Don't let your team mates die"], but in general, if the choice is "chase and make a risky play," or "back off and secure a merc camp" -- back off and secure that camp.
1% is just as Dangerous as 100%.
If you split your damage across the enemy team, and they focus fire, they'll win. You want your team to surgically remove a dangerous or out of position character as quickly as you can. If someone on your team gets caught, and you don't have a good way to counter initiate, just peel off and reset.
Every Fight Isn't A Fight
If there's nothing to be gained from a fight [no objective, no lane to push], and the fight looks even -- just don't fight if you can put that energy to use elsewhere. Over aggression is almost always detrimental to your team position. No one ever says, "Man, I wish I'd made a better trade at level 3!" People always say: "I wish I hadn't over extended and given the enemy a kill."
Go nova early
Not Nova, but as in, use your abilities as soon as a half-way decent moment presents itself. Don't wait for the perfect moment, because you might get CC'ed, displaced, or nuked to oblivion. A power slide that only gets two bad guys and puts you in position to spread them away is better than never getting to use the abilities. Yes, we all dream of hitting all five of them with power slide. It ain't happening. Catch the carry, stop the heals -- reposition yourself with it. Using is better than losing. Now, this is a very, very general rule [there are some times it makes sense to save abilities, especially ones that may not come up again in a team fight], but in general, if you're having trouble in team fights, play more conservatively and pick better fights [look for when you have numbers up, when someone is low on health, when an enemy whiffed an ult, etc.]
If your ult is up, you want to use it as soon as a good opportunity presents itself. Force fights when you have your ult. It changes the fight, and the more you use it, the more chances you get to use it [if you sit on it for three minutes, that's about two or three uses you've missed of it!] If you have an active item in Smite or LoL, use it liberally.
Ping and Listen to Pings
If I tell you to attack someone, and I'm a tank or support, it probably means I'm blowing my CC to engage. So, like, blow them up? Likewise, if my assassin says "Kill this guy," it probably means I should engage on him. If the ping is suicidal [you noticed the enemy team duck into a nearby bush that your team mate may not have], make a retreat or danger ping. Don't just not go in. In general, it is better to NOT FIGHT than to FIGHT when you may lose.
Let your friends die
If your friend picks a bad fight (2v3, 2v2 where you're at low and they're at full), learn to accept that one death is better for your team than two. Just because I'm Uther doesn't mean I need to support you in a destructive move. I'll just go B or soak some XP.