Find an old, oversized t-shirt. Trace your chosen shape with a sharpie. We cropped the front of the shirt and added a flattering, low back. Cut along the lines with a good pair of fabric sheers, try the shirt on and make any desired alterations!
DIY Tee to Cut Out Bandeau Top Tutorial from Bleached Faded here. Really easy tutorial although Id probably sew wear she has used fabric glue. I would also again wear a tank top or something under it so it's more modest.