I usually commend whoever is friendly and did a good job. Also, if they are willing to accept advice if they seem to be struggling.
If there are people who do all of the above in one group, if the good player did an exceptional job, like they saved us from death, manashift when needed, stuns when needed etc, they get it. If not, I give it to the friendliest player, the one who says hello, communicates, says good job, goodbye etc. I had a tank the other day who was new, and in their hello they added "I'm new to tanking so please bare with me, if you have any advice on how I can do better please let me know." They instantly got my comm for that run. (In case you were wondering, they were actually amazing.)

If I have a run where no one says hello, everyone does their job ok and whatever, then I don't usually rush to comm. If everyone doesn't leave within 2 seconds of the dungeon ending, I'll give it to the tank usually. (I'm healer.) Or whoever is left.

If I have a run where everyone is an ass (rare) of course, no one gets it.