|Don't remember seeing this method here so I'll mention it! When I make darts I start at the point, not the seam! I fold the dart, pin baste it in place and before I start to stitch I bring the bobbin thread up so I have enough top and bottom thread to tie a knot after it is stitched. Place the fabric under the presser foot with the point of the dart so the first stitch will be off the fabric and the second stitch on the fabric at the point. Do not back stitch, stitch the dart to the seam edge. At the seam edge you can back stitch or not, doesn't matter in the seam allowance. Tie the knot at the point and you have a perfect dart every time. When I'm making darts that have two ends I break the stitching in the middle and start at both points. Adds a step but you get better points.