Only optimize when you need to! PixiJS can handle a fair amount of content off the bat
Be mindful of the complexity of your scene. The more objects you add the slower things will end up
Order can help, for example sprite / graphic / sprite / graphic is slower than sprite / sprite / graphic / graphic
Some older mobile devices run things a little slower. Passing in the option useContextAlpha: false and antialias: false to the Renderer or Application can help with performance
Culling is disabled by default as it's often better to do this at an application level or set objects to be cullable = true. If you are GPU-bound it will improve performance; if you are CPU-bound it will degrade performance
If you know the size of them: container.filterArea = new Rectangle(x,y,w,h). This can speed things up as it means the object does not need to be measured
Filters are expensive, using too many will start to slow things down!