I crocheted Lace Round Doily with cotton thread DMC Babylo size 10 and a 2 mm crochet hook. Its size (unblocked) is 17,5 cm (about 7 inches) in diameter. I didn’t block my doily, but you certainly could block yours.
Besides your chosen thread and crochet hook, you will also need a needle to weave in loose ends and a pair of scissors.