Downsize your yarn and your hook. Have a look on the internet - there are plenty of sites that compare yarn and let you know what yarns are the equivalent of discontinued yars. Some even have pictures of the width of the yarns so that you can measure the yarns that you might like to use against the originals. These sites are really helpful if you want to downsize or use a yarn in you stash.
then, of course, you have to swatch..............:'(
My favourite is usually cotton (because of the definition of the stitches), but for some projects I prefer to use acrylic... Also if I can't find a fitting yarn colour in cotton
the crochet hook size is very important I use thin cotton yarn with zero crochet hook this will make it small off course done by sc stitch , hope this was helpful and enjoy :)