When constructing some small 3D Embroidered pieces, it is necessary to stitch shut darts to give shape and curves to the piece. If the darts are small, it can be difficult to use a sewing machine and you might even find that pins get too much in the way, therefore it can be easier to close these darts by hand. Check out the video linked to see it in action.
Using this laddered running stitch, you can easily close darts like these. Take a sewing thread of similar colour to your base fabric and thread it up into the needle of your choice with a single thread, fingertip to elbow in length. Make a small knot in the end and anchor this knot into the narrow end of the dart on your item.
Start by making a small stitch along the length of one side of the dart of a couple of millimetres, draw the thread loosely across to the equivalent point on the other side and make another stitch of a few mm. Go back to the first side and continue up the diverging sides with these stitches of equal length. Once a couple of centimetres worth of dart has been laddered, gently pull the stitches closed to bring the dart evenly together. If you pull it too tight and it bunches, pull along the length of the dart to even out the tension back to being flat.
If your dart is longer than a couple of centimetres, repeat the process stopping every few centimetres to close the dart up to that point to avoid knotting. Once you reach the end, finish with stab stitches or a subtle knot as appropriate for your project.