I took a pair of jeans and converted them into a vertical messenger with an inseam pocket, large fringed pocket, two pockets on the front, and chain detail. I lined it with a distressed polka dot cotton.
First decide the dimensions of your bag, then cut out 2 sides, the front and back,and bottom in both the denim and the lining fabric: remember to cut the fabric larger than you need it for seam allowance (.5in). Sew all the sides of the denim together (*I sewed two straps and small D-Rings into the side seams for the chain), then do the same with the lining so you have two squares. Turn the lining inside out so that the right side of the fabric will be inside the bag. Sew the seams of the denim and lining together. Place the denim and lining fabric for the bottom together, wrong sides touching, and sew them to the bottom, go through the seams to the edge of the fabric. Cut straps to fit your D-Ring hardware and sew into the top seam as you sew the lining to the denim.