Mostly just learn your role in dungeons and ask for tips if your new to a particular dungeon. Each has different strategies and traps. If one person doesn't know how to approach a particular situation its easy to wipe. Most of the people I've seen interact with newbies are pretty friendly. Occasionally you'll get a tank that just want to power through a speed run an tries to drag everyone with him. Fortunately I'm usually healer (dps que times suck) so they can't go far without me.