I made a cover for my Kobo reader (similar to Kindle) I used a piece of cardboard from a cereal box and cut it to fit the Kobo like a book cover - cover front and back and one side. Then made a slip cover over that with cotton. When closing in the edge that the cardboard slipped in, I attached a tab to fold over to the front and secure with hook and loop tape.
To hold the Kobo inplace, I made loops of lace for the four corners. The bottom loops attached under the Kobo with a tiny piece of hook and loop tape.