|Step 1 - Create a series of blind tucks 3/4 inches wide. Each row should just meet the next row. How many tucks to do depends upon your design. For this skirt, I decided to do three rows.
Step 2 - Slash the tucks at intervals 1.5 inches apart, cutting up to, but not past the seamline. Alternate the slashes so that the cuts on one row meet the middle of the "tooth" on the next. It should resemble the way bricks are laid.
Step 3 - Turn the cut edges to the back of the "tooth" so that the raw edges meet in the middle, folding at a 45 degree angle. Press neatly. Repeat for all teeth.
Step 4 - To catch and hold the folds in place, restitch the horizontal tuck seam in a wide zigzag being sure to catch the raw edges underneath the tooth.
This technique is much easier to understand when viewing photos. To see photos of what is described here, visit my blog's tutorial: