This is my SewUseful contest entry. See it for sale on Etsy! http://www.etsy.com/view_listing.php?listing_id=6412485
Step 1: Simple ingredients and words of wisdom
You'll also need a sewing machine, thread, scissors, pins, a pen (not pictured), some velcro, a seam ripper and measuring tape.
Important! Sewing denim is different than sewing other materials. Ideally you should use a special needle made for sewing denim. Also, a zipper foot to substitute for the regular foot on your sewing machine will make sewing this bulky project a lot easier (keep your regular foot close by for finishing the edges though).
Denim is strong - I broke two needles, a pair of scissors and a seam ripper making just two of these little pocket pals. That taught me some lessons I'll pass on to you: Don't force anything and Always cut through the thinnest area possible.
Finally, if you find that the bobbin (bottom) thread becomes loopy as you sew you may need a thicker upper thread. You can also raise the sewing machine's tension setting for the top thread.
Step 2: Slash the jeans
Use your seam ripper to remove the zipper (picture two). Cut through one stitch at a time, ripping about every third stitch. After you've ripped a few stitches this way you may be able to start pulling the zipper away from the fabric to make the going easier. This will be by far the hardest part of this project. Keep the faith.
Optional: if you want this caddy to have a little strap or handle, use scissors to cut up both sides of one of the double sewn seams to make a "cord" (picture three). Cut a piece of this cord 10-12 inches long, or however long you want to make the strap your preferred size.
Step 3: Attach the zipper
Now pin and sew the zipper to the other pocket in the same manner, with the zipper tab down against the other pocket. The pockets will be right side together as you pin and sew.
When you have attached each side of the zipper to a pocket, open the piece up and unzip the zipper. (picture three)
Step 4: Optional step - skip if you're going strapless
Pin the edges here, one next to the other. Make sure that you leave the pins sticking out far enough from the edges as shown, so you will still be able to see them in the next step. DO NOT pin the strap edges on top of each other. Most sewing machines can not handle that kind of thickness and you will end up with a broken needle or worse.
Step 5: Side and bottom seams
Sew along the sides and bottom, about 1/2" from the edge, removing the pins as you go.
Step 6: Finish the edges
Step 7: Flip it
Step 8: Add the velcro
Cut four velcro strips (two pieces of hook side and two pieces of loop side) about 1.5 inches by 1/3 inches. I used this long skinny size because it closed off more of the pocket opening, and because it fit perfectly behind the top pocket seam, meaning I didn't have to show any of my stitches through onto the front of the pocket where the velcro attaches - I can put all my stitches on the backside of that seam (picture two).
Thread a handsewing needle with some thread (preferably matching the velcro or the denim) and attach the velcro however you wish. Put lots of stitches in to make sure the velcro can hold on through the stress of hundreds of rippings apart. I took my first stitch through the denim to anchor the knot, then used small whipstitches.
After you attach one velcro strip, do your best to line up it's mate, pin it in place and sew it on. Do the same with the other pocket and...