Before turning my fabric out the right way, I like to iron the seam where the opening is back so that it is flat and even for sewing when its turned out the right way. Once turned the right way iron your fabric again and hand stitch the opening closed.
Now before sewing the sides down to make a little sleeve I actually marked them first so that I could sew on the closure. Place the book open on the fabric, fold over the fabric each side and pin. Now because my journal actually has a ring binding I found that I had to make a little bit of an allowance for this for opening and shutting so just keep that in mind if you have one similar (I folded on side an inch shorter then the other).
Close the fabric over as if the book is inside and mark each side where you would like to sew your velcro and your ribbon. I used snap closures but with the velcro I would sew a 1 inch square of velcro onto the end of the ribbon and the other half to the fabric cover.
Would love for you to share what you have made over at my Facebook page.