For whatever reason, I've avoided creating custom textures like the plague. Now I'm facing the prospect of needing to do it. So I thought this would be a good chance to field any tips, tricks and suggestions you might have regarding creating textures! Anything you've got, put it out there.
I'll pop this video I found in the depths of YouTube here to start off.
https://youtu.be/TXr7i8iP2IA