Measure your Kindle, or better, measure other Kindle cover.
Take thick cardboard. The thicker it is – the more it will survive and longer it will last. This one is designed to withstand travels all around the world and some everyday urban jungle challenges like spilled coffee.
Cut 2 different pieces – it will provide scaffold for the cover. Don’t make it too thick – it will be hard to sew it later. Don’t make it too thin as well – it will be flabby.
But cardboard alone ain’t going to make a good cover. Look for something cosy to rest your Kindle on! I found this old piece of cloth. It feels nice and is black. Perfect.
Ask around in your town for someone who works with leather. They will have the best glue, much better than those available in local store. I got mine from saddler (he makes saddles – it requires really strong glue).
I decided to use rubber for holding the Kindle. This way you have some flexibility – different models have different sizes but with this method you can easily fit Kindle Classic and Paperwhite 3 in this cover. Glue them to another piece of fabric and then glue it inside the cover.