However you hold the hook and yarn, you need to control the loop on the hook.
While you’re crocheting, you will need to control the crochet loop with the same hand as the one that’s holding the yarn. When making your first chain stitches (as shown left), hold the tail end of the yarn firmly between your thumb and index finger, or your thumb and middle finger. Doing this enables you to control the position of the working loop on the hook as the hook moves in and out of the working loop. The hook should be around 3-5cm from the index finger of the other hand when you are crocheting.