When drawing a spider web, start in the centre of the forehead (in between the eyes) and work your way out. First, draw a plus sign. Work your way up to the hair line by tracing the inner web or an inverted circle, and connecting those curved lines with diagonal ones across your forehead. Keep in mind that it doesn't need to be exactly perfect, as most spider webs aren't when you look at them up close.
For a fine-point line, use MAC Cosmetics Brush 209 (£16.50) with Boot Black Liquid Eye Liner (£17.50) to ensure that it will stay put. You can finish the look with a drawn-on spider if you're artsy, and a bold lip, like MAC D for Danger (£10).