The loop stitch is a fun technique to know because it allows you to add a yarn loop to one - or both - sides of your knitting. You can make the loops whatever length you like, but it'll have the best effect when the loop size is consistent all over. Also be sure to be mindful of the yarn weight you are using, as usually the lighter-weight the yarn, the shorter you will want the loops (otherwise they can look a little straggly).

Below you will find a video teaching you the method: