Beth from The Renegade Seamstress shows how she altered a long denim coat to remove excess fabric at the back. While the fit on the long jacket was good everywhere else, it was too long and too wide at the back. The before and after photos show what a big change this made in the how the coat fits! The extra fabric there caused slouched and added bulk to her waist, but after the alteration the fit is smooth and shows her waistline. Go to her tutorial on eHow to see how to do it.
[photo from The Renegade Seamstress on eHow]