I have some hints for newbies to improve the Performance.
1. Adjust the graphic settings
( lower the View Distance and disable unimportant Effects )
For Example my inGame Settings 
and the best Way to set up your Video Settings is to adjust it directly in the Launcher
For Example my Launcher Video Settings
The Reason for reducing the View Distance is, it reduce uploading Textures in your Ram, which is important for reducing Crits.
Disable Effects helps to reduce FPS Drops(Laggs) while fighting.
The Option "Hide Effects of Mobs" is disabled for the Bossfights, because of Events.
2. Adapting Addons
It should help to sorting out Addons which are not in use. For Example i would not use Addons like ( PBInfo or xBar ) which eats to much FPS, there are better options for this.
ps.
if someone is interested to know which Addons i always used, then i create a List for it with Links.
pps.
if i forgot something or i could add, let me know pm
