Very easy, very quick way to add patterns to your fabrics.
They can be fabrics that you've drawn and painted or fabrics from photos in which you are manipulating.
Patterns are so diverse and you can do so many things with them, if you keep the basics of light and depth to them.
Remember, patterns/textures are not just for fabric!
Try it on skin, scales, etc.
I hope this very basic, simple tutorial helps you.
If so, let me know! I'd love to see.