Oh, I'm sorry, I was misleading; it wasn't "wool" wool, it was acrylic yarn. It wasn't the texture so much as the thinness of it that made it hard to see the stitches. I started again with a single-ply very thick yarn and a much bigger hook, and my sister was down for the weekend, and she helped too. So now I've done a chain, and slip-stich, and single crochet... and my rows kept on getting smaller and smaller, so there's something I'm doing wrong with the turning, so I've unravelled what I did and am starting over again.

I have a tendency to make the tension too tight; I suspect it's due to my long experience with macrame, where one needs to tie the knots tight rather than loose, so something in me rebels against loose stitches, even though one needs the stitches to be loose enough for the hook to go through when doing the next row! Practice will presumably improve this.