Yes, I work in photoshop. I use a Wacom Cintiq 13 tablet. I assemble/collage a base to include everything the character has, like accessories/guns/goggles etc. I then paint over everything. I use the warp tool a LOT. I use many layers. I usually just use default brush tool. I also use texture overlays for many of the fabrics.
Portraits take me about 15 hours to complete.