Dungeoneering basic questions.

I just leveled up all my skills to at least 80,besides dungeoneering. I am lvl 72 "dung" rite now, and would like to lvl 80. I used lamps etc to get to 72. I have really only done it maybe 4 or 5 times at all. So I am a dungeoneering virgin. I would like to play on a team, but I don't know really what i need to do, and I dont think the experts and not gonna play with a newbie, and I understand that. I think the highest lvl i can do is lvl 27. Do I always to make it to the hightest level?. If anyone could suggest any ideas / tips for what i should be doing would be great. Thanks.