I usually say nothing, when I'm dps on my Warrior...just go in, and deal with whatever comes along, best I can.
The other day, I found myself typing things like, "watch for the pats, here...get them first". Or, "everyone but tank, stay away from the dwarf who's whirlwinding, or die!"
No one said anything, but they followed my advice! So, we get to the end, and the tank actually thanks me for the pointers, and help! I said, "I kinda just thought it was a new place for you, so hoped you didn't mind. You did really well, except for that one spot, where you grouped the fire elementals at the top of stairs, instead of the bottom. But, even then, you kept your cool, when it aggroed another four mobs. Most people, who are new to the instance, will either wipe at that point, or have one or two deaths, at least, due to the mobs exploding!"
For reference, this was normal HOL, and I was the only level 80 in the group. It had started kinda "rocky", with a couple of the dps telling this tank she should be level 80, and a bunch of other misinformed crap. They even asked me to tank, and I told them I don't tank pugs, and they should be thankful they had one that was willing to do it.
Overall, it was a delightful run, because I got to be of help to an aspiring tank. I only hope that she continues, because she showed real awareness, and had good skills.
Also, it was a good lesson, for me, in patience, and adapting my attacks, so as to not pull aggro--which was not easy, in light of the difference in gear, and all.
-"Just like a buzzin' fly, I come into your life, I'll float away, like honey in the sun..."--Tim Buckley