It is essential that you prepare all fabric before cutting it out in order to achieve a better fit and a more professional look. Different fabrics will need different care and the label on the fabric bolt will tell you whether the fabric is washable, dry-cleanable, or if it will shrink. I like to take my pen and notepad into the store so I can write this information down whenever I buy material that I’m not familiar with.
The label should tell you whether the fabric has been preshrunk by the manufacturer, or if it will shrink and how much it will shrink.
If the fabric has not yet been preshrunk, and the label says it will shrink more than 1% you are better off to take the time to preshrink it before cutting.
To preshrink washable fabric, simply wash and dry it in the same way you would after the garment is finished. To keep the ends of the fabric from fraying simply sew a seam or serge along the ends before washing and drying. Otherwise you could end up ruining your new material.
To preshrink dry-cleanable fabrics use a steam iron and move the iron horizontally or vertically across the grain of the fabric. Do not go over it diagonally because this will distort the fabric. After steaming the fabric, allow it to dry on a smooth and flat surface until completely dry.
In addition to preparing fabric, other notions such as zippers and trims may also need preshrinking.
Another thing you want to do is make sure that your fabric is on grain before cutting.
To straighten slightly off-grain fabric leave fabric folded lengthwise and pin together the selvages and both ends making sure they line up, then using a steam iron press from the selvage to the fold.
If the fabric is more off-grain and cannot be straightened with an iron, simply pull the fabric in the opposite direction of the slant.
To be on the safe side, make sure to purchase extra fabric than what the pattern says you’ll need.
By following the above steps before cutting the material your finished garment will have a more professional look.