First I traced the journal onto felt and cut out a piece for each side. This will be hidden by the fabric over it eventually, but will make the journal softer. Then I hot glued the felt on the front and back of the cover.
I glued the fabric to the inside of the journal covers, making sure to leave enough room for the book to close. It helps if you cut diagonals on the corners to remove extra fabric. Around the spine I cut a notch in the fabric and folded it under.
I cut a piece of card stock slightly smaller than the inside of the cover and glued it over the raw edges. The journal will close better if you leave some room between the edge of the card stock and the fold.
There it is! I glued a button to the front of the journal, and glued a ribbon to the back (under the cardstock on the inside) to keep this one closed. You could also add a bookmark. If your journal has trouble closing, keep it under something heavy for a week.