When working with any yarn, you have to have the right hook size. The simplest reason for this is, if you have a bigger or smaller hook than what is required for a particular yarn and project, you will end up with looser or tighter stitches. I remember when we were taught crochet in high school and we were only given those very small steel hooks. We had no knowledge of hook sizes and only used those steel hooks to work with mercerized cotton yarn. Most of us (if not all) ended up with curled up doilies. Because of that, most of my classmates lost faith in crochet - simply because they thought they could never make it right. Little did we know that we only had the wrong hook size.
You see, there are different sizing labels for crochet hooks and knitting needles: US, UK/Canadian, Japanese, and Metric. You might think your hook with the size 10/0 is different from another hook with size 6.00 mm. They're just the same. One uses the Japanese sizing label and the other is being labeled in its equivalent metric size.
gauge of the pattern or the yarn. If your gauge doesn't match that of the pattern (or yarn), then you might want to adjust. If you have really tight stitches, use a hook one size bigger. If they're too loose, use a smaller one.
It can be subjective too, you know. There are times when I don't follow the suggested hook size. I always experiment with different kinds of yarn and I always make chains with different hooks to check what looks best.
So that's my small tip for the week. Hope I made some sense!