Commendation System: So who get's your vote?

[Anapingofness]

I feel bad not being able to commendate nice players when I join a duty with my friend. We should still be able to give commendations to the other players. :<

This so much!
I've had several amazing people in my parties that I wasn't able to commend because I was w/ a friend.
It's perfectly acceptable that I cannot commend my friends because we're in a premade group. However, as others have said it is unfair to those players who join up using duty roulette and do an outstanding job.
I hope SE addresses this soon!

but to answer OPs question.
I commend players who are friendly, helpful, and play their role well.
I know it can be difficult to talk in party especially if you're tanking. The game design doesn't exactly encourage party conversation. However, efforts should be made since it really helps make the experience in that dungeon a lot better.