The best way to test if a pattern works is to make a muslin (mock-up) from it and fit the muslin. During her patternmaking class, Sarah fits students' muslins and helps them alter their patterns. Students then create another muslin to test the fit and fine-tune their patterns further. Sometimes three or four muslins are made and fit in order to achieve an absolutely perfect pattern.

Shelley's first skirt muslin needs a little work to get rid of the pulling at the front and to fit her better.	Shelley's second skirt muslin looks much better. The pull lines at the front of the skirt are gone, the waist fits comfortably, and the skirt proportions are flattering.
	Sarah fits Paula's first t-shirt mock-up.
The rest of the group watches as Sarah explains what she is doing to fit Mary Ann's muslin.	Shelley's t-shirt mock-up fits well, but will be even more flattering when she adds a bust dart and neckline shaping.
Margie watches as Sarah fits Joyce's first jacket muslin.	The fit of Joyce's second jacket muslin is a big improvement over her first muslin.
While fitting Margie's first muslin, Sarah explains to her students why certain style lines are more flattering.	The open neckline on Margie's second muslin is very attractive for her body type.
Paula's mock-up needs adjustments in the side seams and sleeves.
Joyce's first t-shirt mock-up is too big and needs some shaping.	After removing the sleeves on Joyce's t-shirt mock-up, Sarah is able to add a dart to the bust and alter the armscye for a flattering fit.