My mother found a dress that she liked, except that it was a bit too short for her taste.
So she asked me to lengthen it a bit.
We decided to cut the bottom 3" off the dress.
I sewed a 7" piece of black fabric (of a similar fabric and texture) onto the dress, then re-attached the three inches I had previously cut off of the bottom.
Hopefully, this way- it doesn't look like some afterthought or alteration. We think it looks more as if it were part of the original dress, than it would if we just stuck the black piece across the bottom