Clean the eyebrow area and let it dry
Comb the eyebrow hairs upward with a spoolie
Choose the spot for the slit
Hold a clean razor or eyebrow trimmer steady
Place a small piece of tape vertically over the eyebrow if you want a guide
Shave a thin vertical line through the eyebrow using light, short strokes
Remove only a few hairs at a time
Check the shape in a mirror after each pass
Stop when the slit is the width you want
Brush the eyebrow back into place
Clean the area and apply a gentle moisturizer if needed