I discovered something that has helped me tremendously in loosening up my bind off stitches without making the row floppy.
When you pull your yarn through while making the stitch on the left needle, whether it's a knit or purl stitch, pull the loop out to measure 3/8 up to 1/2 inch. Actually measure it on a ruler, otherwise it's too easy to revert to small stitches. Once you get the visual perspective of how long you need to pull that stitch out before you take it off the left needle it becomes easier to eyeball it. But in the beginning check it against a ruler.
As you bind off you'll be able to tell if your row is too loose or too tight and can rip back and re-adjust. Doing this has saved me lots of headaches and once the bind off is done correctly and I pull the piece into shape it's amazing how nicely it "fits".
Of course, blocking the piece makes it even nicer.
Good luck and happy knitting. Hope this helps!