Sculpting wrinkles in clothing is way to difficult for me, here's a quick walkthrough of how I like do do things since yesterday;) Been messing around with Marvelous for a few hours, great stuf!
Zremesher helped a lot too, great tool!
Marvelous Design for Pillow sculpting
Zbrush for remeshing
Maya + V-ray for rendering
Eyeon Fusion for comp