A huge amount of lag seems to be related to video settings here are some I do that help, please post if you have others to add or change.

eq commands - /showgrass off /dynamic off /shownames 1 /shadows off /part med

eq options - turn new armor to self only or off. Turn most pixel shadders off shy of 1.1 (yeah eq will look abit less pretty but is way faster). Turn any option you can find to medium aka particals, clip plane distances etc

Im sure there are many others but as my pc is down atm I cant tell you what or where yet. Leave the one that shows the grey aura on though for raids (post effects) and dont go below medium on particles or such as some quest or raids wont show right below medium.