Here's a portrait I completed a while ago for a lady who does riding competitions. She provided the photo and I drew from that, removing the background so they stood out more.
Here's a detail of the horse:
Here's an animation of the various progress scans I made as I was working. It took 24.5 hours all up:
You may notice her face change on the very last stage – I sent along a scan of the finished piece to check that nothing needed to be changed, and my client realised that the photo she had sent me wasn't actually a good likeness at all, and sent me another photo so that I could adjust her face.
For this portrait I used a #B mechanical pencil and an #8B solid graphite pencil, along with various blending tools and erasers. For more information on my portraiture materials, you can look at my tutorial on the subject.