1.) Get a firm cup bra that is one cup size larger than you normally wear.
2.) Remove everything that stretches from the bra including the straps and sides.
Leave the cups attached in the middle because it’s easier to work with the bra if the cups are attached and leave about 1 inch (2.5 cm) on each side of the cups to have something to sew to.
3.) “Stiffen” the bra by applying 2 coats of fabric stiffener available at any fabric or craft store.
Let the 1st coat dry overnight before applying the second coat. This will give added shape and strength before you start adding decorations.
4.) After bra is completely dry, hand sew decorative fabric over each bra cup and center section.
5.) Measure the length needed to extend from the cup to the center of your back.
6.) Measure the width around to center back (where your regular bra normally is)
7.) Create side pieces and straps from heavy interfacing or horsehair interfacing adding about 1–2 inches (2.5–5.1 cm) just in case you gain weight.
Then add decorative fabric to side and back pieces. It’s helpful to use the pieces that you cut off as a pattern and add length to make up for the stretch that you lose when you use non-stretch fabric.
8.) Decorate your bra by sewing beads, sequins, appliques etc to the cups, straps and back on bra.
9.) Add heavy duty skirt/trouser hook & eyes to the back straps to “close the bra”
10.) Add felt to the inside cups and side straps of the bra to absorb sweat and make the bra soft and cushy.