1. Place plastic wrap over balding area, preferably to have the wrap
long enough to stretch all the way around your head and tie it under
your chin, so it is tightly fit to your head.
2. Tape the plastic wrap to contour the head shape, preferable to use
thin strips of clear or masking tape. Beginning at your forehead, place
strips over the plastic wrap at the side edges of your bald area and
work your way inward with more tape strips.

Once you have a complete layer of tape running front-to-back, place
another layer of tape over the first layer, going from side-to-side. Apply
three layers of tape – two layers front-to-back and one side-to-side. The
tape will lock the plastic wrap into a template of your scalp.
3. Use a marker to trace outline of the balding area. The front hairline
should start at least three fingers above your eyebrow. You may also
indicating where you want a part and how you comb your hair.
4. cut away the excess plastic wrap along the outer perimeter line.
How to make custom template