First, you will need to decide what you are going to hold in your organizer, the one picture above is for the car. It has a space for your insurance cards, a pen, tire pressure gauge, paper, scissors and a small flashlight.
You can use almost any kind of place mat, just keep in mind that you will be able to see both sides so you might want one with print on both sides.
Take your place mat and fold it up about a third of the way.
If you want a card pocket, fold down the corner. Sew the corner down first. Do NOT SEW it down to the large section/back of the organizer, just to your front third that you folded up.
Then lay your objects into the fold to see how much room they need. I sewed a seam right besides my folder corner, then I placed my notepad in the center of my place mat and mark how much room I would need on either side of it. After sewing your large pocket for the notepad, I took the left over space on the right side and sewed a seam down the middle to give it too even sized pockets. Those pockets are the right size for a lot of items.
After you are done sewing your pockets, fold up the organizer around the middle panel and mark where your hair elastic needs to go. I used a head band and had to cut a couple inches of length off of it to make it fit snuggly. Go over the hair elastic multiple times to get it secure.
Then throw it in the glove box of your car or your purse, where ever you could use a little bit more organization. I have one in my car, one with my Sunday school stuff and one in my purse. Where would you use one?