Continue reading to see how to do this.
After marking the seam, pin it.
Stitch the seam, starting from inside and overlap slightly. When you get near the fold, stitch on the fold and leave a 1" tail.
Press after stitching.
Clip seam close to stitches and then press open on a ham.
The finished dart. Note: it looks a little funky because I forgot to take a picture of the finished dart until after I had already had it in my notebook for a while.