Rule Number 1:Let the Quest Leader Lead
The Quest Leader is a volunteer and many times has gone through great lengths to prepare for the quest. Even if you know the quest, let the designated leader lead the quest. IF you would like to offer your help, do it in a private tell. Don't undermine the leader. Also, you can't follow the leader by running ahead of the leader.
Rule Number 2:Be Patient
For many of the quests that exist, there can be some waiting at certain points in the quest. Yelling "Let's Go Already" is not only a good way to annoy the leader, but others waiting patiently as well.
Rule Number 3:Prepare
It's a good idea to prepare for the quest so you have an idea what to expect. A good source of information for quests is: http://www.thejackcat.com/AC/Hobbies/Quests.htm
Rule Number 4:Listen & Follow Directions
Most of the time, there is some important information pertinent to the quest that you need to know. So, listen to the Quest Leader and follow the directions.
Rule Number 5:Buff When Necessary
Don't buff for the sake of buffing. The verbage from spell casting can get in the way. Type /filter -spellcasting and this will suppress everyone else's spell casting verbage. Many times, there are so many people on a quest that buffing isn't necessary.
Rule Number 6:Be Prepared
Make sure you have enough Spell Components, Health, Mana, Stamina Potions/Elixirs, Healing Kits, Mana Charges, Arrows, Quivers and Time. These will keep you alive. The last will keep you from sleeping on the couch.
If you follow these rules, everyone will make it through the quest with the prize and alive. The majority of deaths during a quest are directly attributed to people not following the above rules.
Following these rules make questing pleasurable and will increase the likelihood of that person leading a quest again.
Remember, you will lead quests eventually. The question to ask yourself is: "Do I want thirty people like me on a quest I am leading?"