I've been having a lot of fun making satchel bags after I figured out how to make them back in this post. This one was slightly different, so if you want full instructions go here, but here's the little summary of this DIY.
1. Get your fabric. Mine was a weird old heavy canvas jacket. 2. Make two identical rectangles. 3. Make two side-strips and one bottom-strip. 4. Join them all up into a pouch. 5. Make a front-flap (using different fabric for the front of the flap) and attach it to the back of the bag. 6. Place your belt on your bag and sew it securely onto the front flap. 7. I then used a pocket from the coat and put it on the front of my bag so it had an extra embellishment. 8. I added a strap which was just an old fabric belt. But you could make a strap by cutting a strip of fabric, folding over and sewing the raw edges together, flipping it inside out and then sewing it onto the sides of the bag.
Good luck to anyone who gives making a satchel bag a go, and please email me a photo if you do!