How do you stop lagging in dalaran

Lag in Dalaran is one of those things that has plagued WoW ever since it hit the live servers. There is not really anything you can do about it. It has to do with how many people are in the city at the same time. The servers just aren't quite capable of putting up with several hundred people in the same area at the same time.

Wintersgrasp used to be the same way during battles, then blizzard put in mechanics to limit the number of people that can take part in the battle. This helped quite alot.

One thing that you could try is upgrading your computer's RAM and Video Card. This is not a guaranteed fix though, as even people with top of the line computer systems can lag a bit in Dalaran.