In this tutorial, we learn how to make stencils in GIMP. Start with heads or faces if you are new to this. Then, use the rectangle tool to select the head. Then, go to image and fir canvas to selection. Now, remove the background by using the background tool. Once finished, go to colors, then threshold. The image should turn black and white. Turn the dial to the right, then turn it to the left to make it lighter and darker. Find the spot to where it shows detail but it's not distorted, then hit "ok". Now you can use this as your stencil, enjoy!