Options
Different types of interfacing such as sew-in interfacing, fusible interfacing, woven and nonwoven interfacing can be used. While selecting an interfacing option, consider the weight of the fabric, the location of the interfacing, the amount of crispness required and the type of care that the fabric will receive. The chosen interfacing shouldn't be heavier than the fabric or else the fabric will droop due to excessive weight.
Testing
Test the interfacing on a small part or scrap before applying it on the entire fabric. In case the pattern doesn't come out well, it can be changed. Besides, testing the interfacing is also important to gauge its compatibility with the fabric. Certain fabrics such as acetate, velvets, brocades, vinyl, rayon, and fake furs can't endure the fusing heat. Embroidered, sequined or beaded fabrics are also incompatible with heat.
Preshrinking
Preshrinking the interfacing is vital to achieve the desired results. For tricot knits, washable woven and wefts, the interfacing must be folded loosely and immersed in a hot water tub. Once the water cools down to normal room temperature, a towel can be used to remove excess moisture.
Layout Execution
Trim the interfacing using pinking shears if the interfacing covers only a part of a pattern piece, such as the back or front of a jacket, so that the conspicuous line on the right side can be obliterated. For firm nonwoven interfacing, the pattern pieces can be arranged in any direction. For cross stretch and lengthwise stable interfacing, the pattern pieces can be laid similar to woven fabrics.