Being new to a fight/dungeon/ect does not mean one is carried by the rest of the group as some suggest.

Yes, some effort should be made by the newbie but I find that the "experienced" players tend to be... well, not very forgiving. People just wanna get their stuff done and move on, forget community building yo- I'm most important! My needs! MY TIME!! MY NEEDS!!!! DON'T YOU NOOBS GET IT?!?!!!11111oneoneoneone

Sarcasm aside, it does cut both ways. Both parties have to make an effort and both parties need to show respect for each others time and the people behind the character.

Personally, I will always ask for highlights of a fight/dungeon or I will at least look it up on wiki. Video guides tend to irritate me so I avoid watching them.
Still, the best teacher is when one enters the fight and actually does it. I usually catch on pretty quickly and am open to suggestions for improvement.

That being said, whenever I'm doing a fight or dungeon for the first time I try to tip the scales in my favor by making a premade group. At the very least I try to fill in as many spots as I can with people who won't mind a wipe or three if need be. That also means that the few pug members that do join my group also need to be prepared for a few wipes or maybe even a rough run without throwing a fit like a petulant child.