Adding more detail and making a texture look real takes some effort. The know-how is in a tutorial in this series: Creating a Realistic Head in Blender – part 08 – Clothing Textures. In the 8th of the series, CG Cookie Blender is working on the clothes. So, don’t let the title put you off.
https://www.youtube.com/watch?v=4B6wPgNdWQ0
You’ll notice Cycles and the Node Editor are not used in the early creation part. So, it is mostly an older workflow. Still, I found the video helpful on a number of levels.