I love all of these textures—no wonder, that's the reason I decided to teach this class!:D—and usually use them for different purposes:

— Noise is my usual go-to technique for anything featuring gradients,
— Organic Grain is my favourite to add a little bit of unevenness to the vector designs with solid colours (such as surface patterns and illustrations),
— Film Grain is my favourite for photographs and digital collages,
— and I use Fibers when I need something a bit more organic and complex to cover large solid colour areas in illustrations, designs or collages.

And of course Sandstone is indispensable for creating quick mock-ups, and even better when combined with a few of the other textures as well for a more complex look!

And here are a few textured examples...

 

Textured using Organic Grain & Sandstone.

 

The poster has 3 instances of the Noise applied to it: 2 noise layer over the entire composition & a separate noise filter applied to the actual design layer (which creates a slightly different effect due to how it blends with the graphics in the layer by default).

 

Poster mock-up is textured using Organic Fibers & Sandstone; background is textured using Noise, Organic Grain & 2 Organic Fibers textures (with different settings and fibers patterns).

 

Textured using multiple Organic Fibers textures.

 

Thanks for watching, and I cannot wait to see your experiments as well!

—Evgeniya