Griddle Stitch is a classic when it comes to dishcloths. This is because it is a very fixed pattern – without many and large holes. It may, at first glance, seem a bit messy (as the name also suggests), but because it is continuous and repetitive, there is control over the mess. It’s quite charming 🙂
I do not make borders on my Dishcloth in Griddle Stitch. I think a border gives it a soft and feminine look and I am quite fond of the raw edge. It is a completely personal taste and the border can always be added. If you crochet without an edge, it requires that you crochet very straight and with the same firmness throughout the cloth, so you get a tight look, and the cloth is nice and square.
If you want to crochet a border, for a cloth like this, I would recommend making it with single crochets (sc) all the way around. At the corners you make 3-4 single crochets together (depending on whether you crochet very firmly or loosely), so that it becomes nice and square. On the sides I adjust, as I crochet along. So you make one side at a time and look at it. If necessary, change it if it is too tight / loose. A border is a good idea, if you are not so experienced yet, and would like to hide small flaws. Or just think it gives the best finish.