Notes:

0:34 What is a tile?

0:51 What is a tileset?

1:15 Tile atlas example from Super Mario Bros.

1:28 What is a tile atlas?

3:56 In general, you want to ensure the left and right sides of the tile correspond with each other

4:39 Start painting

5:35 Select a lighter shade, create a new layer, and add more detail

5:46 Add more layers of highlight as needed and use a lighter shade each time

6:05 Create additional layers for different parts of the tile

6:41 Paint shadows on separate layers

7:50 Duplicate the dirt layer

7:58 Add noise to the layer

8:03 Rasterize the image

8:09 Select Uniform (and Monochromatic if you want your noise to be only black and white)

8:24 Scale it up to make the noise look like a pattern rather than noise

8:33 Delete the vector mask