Take a diamond shape diagram on the top of the head.
Starting in the back or side take a medium weave or slice, color the hair and fold the foil and work across the diamond shape taking medium weaves. As the head gets wider just use 2 foils to go across the head.
You can foil horizontally, like the bottom picture shows or diagtonally which would give a softer look.
Then the finished look will look like it's darker at the bottom & back with the top fully foiled, great for Bobs & short hair.