You can make a quick illustration from a portrait in very easy way. I recommend to work with a big canvas and high resolution (7000px and 300ppp). We’ll use a white layer in the bottom and 10 pixels black wide Brush Tool. With Photoshop, create the outline with the Pen Tool (P) and stroking the path with the Brush Tool, trying to make it as close as you can. Several layers can be used, where you can paint one over another and erase without messing up with other layers. It’s..