Start by layering the tape all over every side of the bag making sure to flatten the side you are taping before laying down the tape. The bag can be folded in various ways so that each side is flat before covering it with tape.
Always trim the tape with the X-acto knife as you go along.
Then trim off excess or fold over to reinforce corners and edges.
Finish trimming excess tape around all sides.
Taping the inside of the bag - To make the bag reusable, waterproof, and “goo”-proof, the inside of the bag must be thoroughly covered in tape. That way a damp cloth can be used to wipe down the inside after each use.
Start by cutting along one edge of the bag all the way to the bottom flap. Then cut two sides of the bottom flap. First the short side then the long side.
Then start taping the entire inside of the bag. Working with the natural folds and corners of the bag. Make the bottom pieces longer to strengthen the bottom of the bag a bit better. Always trim as you go so that the tape doesn't stick together or get bunched up and mess up the project.
Put the bag back together and trim any excess tape. Be sure to have about 1/4 inch overage when doing the sides so when you go to put the bag back together, it's easy to stick the bag back together. Follow the bags natural folds, etc…
Making the flap! - Make a double-sided rectangle 4 1/2 " in width and about 6" in length. Both sides should be taped…
Lay the flap on the back side of the bag about 2" down from the top and with a long piece of tape that goes from the bottom of the bag to the top of the flap, securing it in place and creating the trim on the bag. Flip over when finished
Trim the flap to any shape you like. For this flap I cut off the corners. Then add Velcro dots.