A dart is a wedge-shaped seam that molds a flat piece of fabric so that it fits smoothly over a rounded area of the body, for example around hips, bust or the top of the head. Darts should always be stitched from the broad end towards the point, tapering as narrowly as possible to avoid unsightly cones.
Fold the fabric with right sides together so that the dart lines meet. Pin or baste dart lines together, beginning from the point, but then machine stitch dart starting from the broad end. Secure seam ends with backstitching or knot ends of thread. First press darts flat, then press to one side, always pressing from the broad end to the point. Usually bust darts are pressed downwards and waist darts (vertical darts) are pressed towards the centre of the garment.
If your fabric is thick, darts can be flattened by cutting back the fabric. First sew a simple dart as described above. On broad darts, trim the dart to about 1 to 1.5 cm beside the stitching line. Press edges apart and then press the darts straight down in position. Slash narrower darts in the middle to about 5 cm before the point, then press darts as previously described.
When a dart is expected to look like a carefully pressed-apart seam or will be topstitched, it should be backed with a strip of self-fabric or lining. This strip should be cut out on the bias about 3 cm wide and about 2 cm longer than the actual dart. Pin the middle of the strip on one side of the basted dart (if the dart is to be topstitched, on the side destined for the decorative topstitching). Stitch the dart from the other side, including the strip. Then press the dart to one side and the folded strip (double layer) of the strip to the other side.
Darts with points at both ends:
Darts with points at both ends should be stitched in two separate sections, i.e., begin in the centre of the dart each time and stitch towards the point. As the folds of these darts are somewhat shorter than the stitching line, they should be slashed along the middle until almost as far as the stitching and then pressed towards the centre front or back.