The first step is to create a large sheet of duct tape 8.5 inches by 7 inches. This is the key to any duct tape project, with a sheet of tape you can make anything! Rip a strip of tape at least 8.5 inches in length and place sticky side up on your working surface. rip a second piece of equal length and place sticky side down half way over the first strip. Fold the rest of the strip facing up over the second strip. Flip over the two strips and place a third strip sticky side down covering the remaining sticky part of the second strip. Flip the sheet again and continue extending the size of the sheet until the needed size is satisfied.
Make a sheet of tape (as in the first step) larger than your ID card. Cut the sheet so the outside part of the frame is slightly larger than the height and width of the ID. Cut the inside .5 centimeters, (big enough you can see you picture and info, but small enough the ID can't fall through the opening. Now trim the outside so it is slightly larger in all directions than your ID. Tape three sides of this window to the inside of your wallet, or on top of the credit card holder. It'll take a some trial an error to get it right, but it will be a great addition to the wallet. When your done, the ID should be able to slide into the untaped side of the holder, and once in, not fall through the open window.
This is the completed wallet. There are an infinite ways to personalize this design. Some ideas I've embeded in mine are coin pockets within the large bill pocket and placing flaps on the credit card holders so business cards don't fall out when the wallet gets dropped.