Performance Tips

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

Use Spritesheets where possible to minimize total textures
Sprites can be batched with up to 16 different textures (dependent on hardware)
This is the fastest way to render content
On older devices use smaller low resolution textures
Add the extention @0.5x.png to the 50% scale-down spritesheet so PixiJS will visually-double them automatically
Draw order can be important

Graphics objects are fastest when they are not modified constantly (not including the transform, alpha or tint!)
Graphics objects are batched when under a certain size (100 points or smaller)
Small Graphics objects are as fast as Sprites (rectangles, triangles)
Using 100s of graphics complex objects can be slow, in this instance use sprites (you can create a texture)

Textures are automatically managed by a Texture Garbage Collector
You can also manage them yourself by using texture.destroy()
If you plan to destroy more than one at once add a random delay to their destruction to remove freezing
Delay texture destroy if you plan to delete a lot of textures yourself

Avoid changing it on every frame as this can be expensive (each time it draws to a canvas and then uploads to GPU)
Bitmap Text gives much better performance for dynamically changing text
Text resolution matches the renderer resolution, decrease resolution yourself by setting the resolution property, which can consume less memory

Masks can be expensive if too many are used: e.g., 100s of masks will really slow things down
Axis-aligned Rectangle masks are the fastest (as they use scissor rect)
Graphics masks are second fastest (as they use the stencil buffer)
Sprite masks are the third fastest (they use filters). They are really expensive. Do not use too many in your scene!

Release memory: container.filters = null
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!

If an object has no interactive children use interactiveChildren = false. The event system will then be able to avoid crawling through the object
Setting hitArea = new Rectangle(x,y,w,h) as above should stop the event system from crawling through the object