- You're pulling the working yarn too tight as you work. Try loosening up your tension by adjusting how you hold the yarn.
- The loop is sitting on the skinny end of the hook. Make sure that when you finish the stitch, the loop on the hook is on the fat portion of the hook, not near the hook part.
- The hook's too small for the yarn you're working with. By switching to a larger hook, you can make bigger stitches that are easier to work with.
To keep from having too-tight stitches ever again, make sure you're checking your gauge against the pattern before you begin to crochet. Taking the time to make a gauge swatch early on saves you serious time in the long run.