Gauge isn’t really important

You could use any cotton along with it’s recommended hook size but remember the finished item might be bigger or smaller than 8 inches in diameter.

I love cotton dishcloths and especially if they have some texture.

fpdc (front post double crochet) is what adds some texture to the front of the dishcloth. It’s easy to do, it’s just a dc that’s worked around the post of the dc in the previous round instead of into the top of it. (see photo for hook position).