Jackets come in many different styles, from casual windbreakers and fleece jackets to formal suit jackets. Unless you're an expert clothing designer, you'll probably want to start with a jacket pattern that you can modify to match your design. How the finished jacket will look depends not only on the style but also on the color and type of fabric you make it from. You can further customize your jacket design by the size and style of buttons or fasteners you choose.
Design a Jacket
Decide what length you want the jacket. Although many jackets end just below the hips, they can be cropped above the waist or sewn as long as trench coats.
Decide how fitted you want the jacket. Casual jackets are often loose, while dressy jackets tend to be more closely fitted in the side and front seams.
Choose a sleeve style for the jacket. Although most jackets have long sleeves, jackets worn with dresses, such as boleros, often have short sleeves. Long sleeves can have cuffs or elastic at the wrists.
Pick a collar style for the jacket. You may want a windbreaker or fleece jacket to have a hood, while suit-style jackets often have lapels or collars.
Select a closure style for the jacket. Jackets may pull over the head, zip in the front, use an overlap with one or two rows of buttons or close with just a belt.
Choose a color, or colors, and fabric type for the jacket. Polar fleece works well for warm, casual jackets, while nylon is best for windbreakers. Suit jackets can be made from polyester blends, gabardine or wool, and evening jackets can be made from satin or other dressy materials.
Choose and Modify the Patterns
Look through the pattern catalogs in a fabric store or online to find a jacket pattern that matches your design as closely as possible.
Cut out the pattern pieces you need, using the cutting lines for the appropriate size.
Make any basic alterations to the patterns, such as shortening or lengthening, first. Many patterns have markings where you can cut or fold the pattern to make it shorter or add paper to make it longer.
Make any modifications to the neckline, collar or sleeve patterns.
Make or modify patterns for any extra features you want on the jacket, such as pockets or a belt. Make sure to leave extra room (1/4 to 5/8 inch) on the edges of each pattern for seam allowance.
If you modify the jacket patterns heavily, or make them from scratch, you may want to test the patterns by cutting and sewing them with cheap cotton, such as muslin, first. You can then adjust the patterns as needed before working with the real jacket fabric.