One of my favourite features of the Procreate app is the ability to watch back your process. I'm first to admit that I don't plan my portraits clearly in advance and I don't stick to a specific style. I'm still searching for 'my' style.
This is the process video for my portrait "Sheridan" (2015). I'm sharing it because it shows me trying a few different styles and techniques, and shows me making lots of mistakes. You can learn so much watching other peoples process videos, but also from watching your own. It makes it easier to pinpoint when a portrait goes wrong, or what single brush stroke brings the whole piece together.
Click on the image below to go to the video: