In my sewing lately I have been lowering quite a few darts. For years this was something that I didn't know should be done or how to do it. Yet getting the dart in the right position is crucial to a good fit. The good news is that it is quite simple to do, and so here is a quick tutorial showing you an easy way to do it! First determine the correct placement of the dart. The end of the dart should point to the fullest part of the bust, but end about 1" from that point. For the top I am making, I sewed up a muslin and from that determined that the dart needed to be lowered by 1". If you don't plan to sew up a muslin (and I often don't - there are no sewing police!), take a moment to pin the pattern paper to the person who the garment is for (a la the Palmer/Pletsch method) and check the dart placement. To lower the dart, keeping your ruler parallel to the grain line, mark the new dart point by the amount the fitting showed it needs to change.
Cut out the old dart. and shift it down so that the point of the cut out dart is on the new marked point. Tape in place.
Slide a piece of paper under the pattern and tape in place. Following the curve of the side seam, connect the top of the blouse to the newly placed dart.
Blend the bottom of the dart back into the side seam.
Cut off the excess paper and you have your altered pattern piece ready to go! To raise the dart, just follow the exact same steps, but move the cut out dart up the appropriate amount. Happy Sewing!