To crochet a Christmas tree skirt, you will need a crochet hook, yarn in a festive color, and a stitch marker. You can begin by chaining 4 and then single crocheting around the chain, making sure to keep your stitches close together. Once you have reached the end of the chain, join the first and last stitch with a slip stitch. Place your stitch marker at the beginning of the round and continue to work in rounds, increasing the number of stitches in each round until you reach the desired size. Once you have completed your skirt, finish it off by weaving in the ends.