Here is the example of what I was able to do in about 3 hours (Sorry I was taking my time and enjoying my weekend). It would go a lot faster if I had several projects lined up and all the images downloaded ahead of time. I used a drawing tablet for this.
Here is the set up. It takes about 10 mins
- Change the Angle (Flip).
- Change the Proportions by Skewing
- Set up the Layers: Action Layer - where I did most of the tracing, and Hair Layer- where i can experiment with the hairstyles.
- Grayscale the image and use a Blue Color over the Grayed Image, so that it is easier to see my lines from the references. "[" and "]" resizes brush size. Go to 1pixel thin.
After all the preparation the rest of the sketching takes relatively less time. It took me roughly 30mins to do this. My speed bumps were my standards, as with any such work. Lower them and power through. After finishing with all the lines, Merge it all, and make a large brush with half opacity.