I have already made a few things for my Nissan Cube to make it pretty
I figured I would make a pretty trash bag. :)
Prepare your fabric. Here I used some waterproof military pants for this project.
Prepare straps fabric
Begin sewing the waterproof part (which will be the inside of the trash bag).
Sew the sides and bottom, then box corner the fabric
Then move onto the outer fabric of the trash bag, sew the sides and bottom, and make boxed corners
Put the inner bag inside the outer bag, wrong sides together
Make the straps
Turn the straps inside out
Stick one end of the strap inside the fold of the top of the bag
Top stitch the top of the bag
Tie the straps around the shift knob of your car! Voila!