Take your skirt and lay it on top of your fabric (lined up with the correct panel). Pin on each side of your dart at the waist and one pin where the dart ends. Fold fabric at the seam you just sewed and pin at the same places on the opposite side. On one side, fold fabric (right sides together) so the waist pins are together. Sew your dart where the waist pins meet, diagonally and downwards, towards the single pin, you will basically sew off of the fabric when you reach the single pin. You will do this same thing for all of your darts on your skirt. Press the darts from the wrong side of the fabric towards the center seams.