I watched the video on a demo project and it says that to prevent the last stitch from being loose one can just pass the stitch without working it. That doesn’t seem to work for me—it’s probably something very basic, I can’t seem to get around to it and it creates a really ugly border.
I’ve always heard slip the “first” stitch of each row. Try pulling the last stitch a little tighter and slip the first stitch and see if that helps.
I also ussually just slip the first stitch. OSmetimes working it through the back loop can also help keep it tighter