What does it take to be a good RL?

[Farah]

You have to become a human boss mods addon.

This is what you should avoid as a raid leader; there are plenty of voice packs/WAs for boss mod addons that do precisely this already. Make important calls and don't overly clutter voice as was mentioned above.

[Kief]

Outside of the ideas already presented in the thread. It is also important that you have COMPLETE understanding of the fights you are doing, so if shit hits the fan during a pull you can deviate from the strategy to a solid contingency plan that you come up with on the fly because of said understanding for the fights mechanics.
There is NOTHING worse than a raidleader that does not think ahead and thinks it's a wipe just because everything isn't going according to the pattern you had hoped for.

What separates a good raidleader from a bad one is the ability to foresee the next 30 seconds-1 minute in the fight and play it out in your head ahead of time, knowing what you expect and need everyone in your group to do at any given moment.

Finally, as a disclaimer for literally all of the advice you've gotten in this thread - it ONLY applies to mythic raiding, since anything below mythic really does not require any coordination rather than agreeing on a plan on how your raid wants to do something. I do NOT say this to take away from players raiding only heroic, but clearing raids on heroic is PuG-content after 2-3 weeks of a raid instance, and any guild that would consider themselves a "raiding guild" will NOT struggle in Heroic if you use voice comms and an organized group of people to do it. A raidleader is just not neccessary at this level of play outside of very few select things like being the one handling invites and the logistics during the raid. The encounters will play themselves out.

[crusadernero]

By looking at the leaders of the PUG raids I join, bad gear is important.

[Marrilaife]

I would say successful raids are combination of both bit toxic and chill environment, it should be balanced. Sometimes you need to shout at people, to wake them up, to realize, they fucking up. If they constantly failing, even after deep explanation of what to do.

People then would not want to be shouted at them, and improve and do stuff the right way, at least they will try harder. Then you can have mostly chill atmosphere on raid.

What I see wrong with many raid leaders is they believe "shouting at people will make them shape up". Nope, being more precise in your criticism will. There are WAY too many raid leaders that generalize, for example "healing is too low!" or "more dps on add!" but they never go down to the logs and check who is actually dragging the group down, which healer isn't healing correct targets or running oom too quickly, which dps is padding instead of switching to add and so forth.

Stop throwing everyone into the same sack of potatoes and start pin pointing who is trying to avoid doing their job and having easy life at the expense of the rest of the team.

If someone died, check did they stand in the fire? Did someone else run over them and dropped some debuff on them (Zek'voz lazors for example)? Did healers not heal them (Vectis omega vector for example)?

Also appreciate your good players, notice if someone is always covering the missing soaks or focusing interrupts while the rest doesn't give a damn. Sometimes your bigger hero isn't the guy topping the meters but one that prevented a raid-wipe mechanic from going through.

And as a raid leader, always have a clear plan. Don't just "wing it" who's gonna carry orbs on Ghuun or how many people pass at once through Mother's doors. You don't have to overplan it, but have a basic plan and adjust it if something doesn't work out.

[D3athsting]

By looking at the leaders of the PUG raids I join, bad gear is important.

For guild raids bad attitude is important together with hysteria, but most important you have to vent your irl frustrations in game

[crusadernero]

For guild raids bad attitude is important together with hysteria, but most important you have to vent your irl frustrations in game

Yes this is very important! critical for raiding