- 1). Take the measurements of your body that the pattern directs, usually bust, waist, hip, bicep, hip length, arm length, and bust point to center waistline. Record these measurements in the table on the pattern directions. Note any differences between the standard measurement for your size and your own measurements.
- 2). Cut out the pattern pieces and make the following adjustments to them so they fit your measurements: Adjust the length of the bodice and the width at the waist by adding or subtracting tissue, and adjust your cup size as well. Adjust the length of the skirt and the sleeves to fit your actual measurements. Adjust the side seam of the bodice if necessary. Other adjustments will be made in the fitting stage.
- 3). Wash and dry the muslin or gingham fabric. Iron it flat. Lay out the newly adjusted sloper pattern pieces on the fabric and cut them out. Transfer markings to the fabric.
- 4). Assemble the sloper pattern according to the directions on the pattern sheet, but without adding the sleeves yet. Use a long stitch, as you will disassemble it later. With your normal underwear on, try on your sleeveless fitting shell. Pin the center fronts together along the seam line. Check to make sure the bust line is positioned correctly over your bust points and that the waistline rests at your true waist.
- 5). Pinch the side seam at the bust. You should be able to pinch out a 3/4-inch-wide piece at each side. Check to make sure you can pinch 1/4 inch on each side at the waist. The pinch should be 1/2 inch at the hips. This is for wearing ease. Your muslin will be a tight-fitting garment, but you can add ease to any garment you design by using it
- 6). Check the shoulder width. Select the correct armhole seam line to use. This line should hit the top point of your shoulder exactly. Turn in the seam allowance of the armhole to judge the fit. Check the armhole depth; the lowest point should be 1 to 1.5 inches below your armpit. Now sew in the sleeves and try on the muslin again.
- 7). Check the fit of the chest and make adjustments if it is too hollow or narrow. Check the fit across the back and adjust if your back is broad or narrow, according to the pattern directions. You can also alter the muslin for square or sloping shoulders, and you can adjust the neckline if it is too tight, loose or high. Sleeve adjustments can be made for a large upper arm.
- 8). Remove your muslin shell and take it apart at the seams and darts. Press the pieces with a warm iron. Transfer all your alterations to the fitting pattern tissue. Redraw the lines and reposition the pattern markings, such as the dart lines. Iron your new pattern to fusible interfacing to preserve it, or trace it onto sturdy tracing paper.
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