I just made this knitting needle organizer for myself. I pretty much followed the design of other ones I’ve seen, but I added a feature I’m proud of: the back row is adapted to be able to hold long needles or short needles. That is: each slot in that row can hold either a tall pair of needles, or a short pair.
My trick for the back row was this: the fabric of the back row does not go all the way down to the bottom. It stops, two inches short of the bottom, and folds back up, behind itself. When you slide the knitting needles into the slot, you can either catch it in the fold, for the short needles, or angle it behind the fold, so it goes all the way to the bottom.
Other than that hidden trick in the back row, it’s pretty much what-you-see-is-what-you-get. I’d give written instructions, but I think the pictures pretty much say it all! It wasn’t that hard to make. The hardest part was sewing the bias edging in a fairly even way. The ruler in the pocket should give you an idea of its dimensions.