step 3 / Working with your muslin connecting strips, finish each of the short edges on each of these pieces with an overlock stitch using your serger. (If you do not have a serger, use your sewing machine’s overlock stitch or a zig-zag stitch.) Set these connecting pieces aside for now.
step 4 / Working with one of your ruffle pieces, stitch a line of gathering stitches 1/8″ and 1/4″ from the unfinished long edge. Repeat with each of your ruffle pieces from all four tiers. Gently pull on the bobbin thread of your gathering stitches to ruffle each of your pieces. You will need to gather each piece so it is shortened by approximately 50%.
step 5 / Working with one of your short tier 2 ruffles and one of your short (5.5×29.5″) muslin tier 2 connecting strips, adjust the gathers so the ruffled piece is the same width as the muslin piece. Pin the pieces together, right sides facing, and stitch together with a 1/2″ seam. Finish your seam with an overlock stitch on your serger or a zig-zag stitch on your sewing machine. Repeat with the other short tier 2 ruffle and the remaining short tier 2 muslin connecting strip. You will repeat this step with the each of the long tier 2 ruffle pieces and the long muslin tier 2 connecting strips, connecting one ruffle piece to one connecting strip.
When all of your tier 2 ruffles and connecting strips are sewn together, move on and do the same with all of your tier 3 ruffle and muslin connecting strips, and then all of your tier 4 ruffle and muslin connecting strips. Be sure to sew the short ruffles to the short connecting strips and the long ruffles to the long connecting strips in each tier.
step 6 / Place one of your completed short tier 4 panels face up on your work surface. Place one of the short tier 3 panels face up on top of the tier 4 piece, aligning the top raw edges of each panel, so that the right side of the tier 4 panel faces the wrong side of the tier 3 panel. Layer the tier 2 panel on top of the tier 3 and 4 panels in the same manner. Pin all three layers together, and baste them together along their top edge using a 1/4″ seam. Working with one of your short tier 1 ruffle pieces, adjust the gathers on the piece so that it is the same width as your stacked lower tiers. Pin the ruffle face up on top of the lower tiers, so that the wrong side of the ruffle piece faces the right side of the lower tiers, and baste stitch the ruffle on top of stacked lower tiers 1/4″ from the top raw edge. One short side of your crib skirt is complete!
Now, repeat this step with your remaining short tier 2, 3 and 4 panels and your remaining short tier 1 ruffles. Then move on and do the same with your long tier 2, 3 and 4 panels and tier 1 ruffles. At the end of this step, you will have two complete stacked short ruffled sides for your crib skirt and two complete stacked long ruffled sides.
step 7 / Use your washable ink marker to mark a 1/2″ square at each of the corners of your muslin platform. Trim these squares away. Working on one of the long sides of your platform piece, pin one of your long ruffled panels to this side, right sides facing, aligning the top raw edges of the pieces. Stitch together using a 1/2″ seam. Finish the seam with an overlock stitch on your serger or a zig-zag stitch on your machine. Repeat on the remaining sides of your platform piece, matching the short sides with the short ruffled pieces and the remaining long side with the remaining long ruffled piece.
Hooray! You are finished!