Turn the cup back over and interpret the pictures made by the leaves.
Steve Roud, in A Pocket Guide to Superstitions of the British Isles, says that this methd of divination has been popular for around 300 years, with the first recorded references to it being made around the late 1720s. The earliest three references are between 1726 and 1731: he believes that this closeness indicates it was fashionable and new at the time. Many early references refer to coffee grounds, before tea overtook them in popularity.