David Letterman has them, People magazine has them and now Sew News has its own Top 10 list--from alteration and fitting expert Mary Roehr.
1 Make a muslin fitting shell.
Making a muslin or test copy to use for pattern alterations, just as couturiers do for their clients, helps you fit yourself and/or those for whom you sew. Most pattern companies sell basic fitting patterns for dresses and pants, such as Vogue Patterns 1003 and 1004 or McCall's 3740.
After adjusting the muslin, carefully release the stitching and trace each piece onto pattern paper or nonwoven interfacing for even more permanency. Whenever you purchase a new pattern, lay it on top of this master pattern to adjust for length and width; dart placement; elbow and knee location; armhole and neck depth; amount of wearing ease; and any other alterations you've made.
Before making a muslin, consider the following points, and know you may have to adjust it from time to time for figure variations and weight gain or loss. For more information on making a muslin, watch for "Make it Fit" in the October '04 Sew News.
2 Allow for figure variations.
No one is symmetrical. Even if the differences are minor, everyone has one longer arm or leg, one higher hip or shoulder, or numerous other figure variations that require extra attention. The amounts may be slight (1/4" or less) or as much as several inches. Righthanded people tend to have longer arms and legs on the right side while the opposite is true for left-handed people.
Many women experience differences in bra-cup sizes, or variations from left to right in the arms, buttocks, thighs, calves and feet. Figure variations increase or become more predominant as we age, so always mark, measure, fit and alter both sides of the body for proper fit.
3 Be aware of your comfort level.
People are different, and they prefer different amounts of wearing ease (the extra fabric allowed for movement beyond actual body measurements) in their clothing. A waistband with 1" of ease may feel constricting for one person and loose on another.
Plus-size and tall people need more ease to accommodate larger body proportions while petites can sometimes use less than the standard pattern ease. Adjusting ease takes time and experimentation but can be one of the greatest contributing factors to a comfortable fit.