Look at your brows closely in the mirror. Decide what basic shape they are.
Go to the catalog that matches your brow shape.
Find your brow thickness by measuring from the thickest part of your brow (A to B). Anything under 1/4" is thin. A measurement over 3/8" is considered thick.
The line connection points A to B is the Brow Length. Use string to measure yourself as it curves around your face. Generally, long is 2 3/8" and short is 1 1/2".
Select 3-4 shapes from the catalog that match your thickness, length, and shape. For best results, try to go a little wider than your current brow.
Order your stencils and get excited!