My 2 cents. When I was a fresh lvl 50 dps doing hm fp. I always say "Hi, this is my 1st time here, I really appreciate any advice" And everyone was very helpful and explained the fight to me . Saying "sorry" after a bad pull or accidenly break CC is the proper manner. Sometimes we wiped and gave up the fp but people wasn't mad at each other. Just start with "hello, howdy etc" at the start of the fp can improve the communication part later. On my 2nd toon as a tank, I have exp from playing the dps so thing went pretty smooth. if some1 haven't gotten to lvl 55 in the group. I will ask full run or quick run before we start. And ask "everyone know the fight?" or give a quick explanation before every boss fight. Got a lot of friend thx to chatting while doing fp ( even in terribad fp run )