Tea-leaf reading is thought to have originated in ancient China. The pattern left behind by tealeaves was examined for signs & omens. The practice spread after tea was imported to the Western world, particularly in Europe.
There are traditional meanings credited to various shapes, but imagination & intuition are what are needed.
I've done a few tea-leaf readings upon request. Each time I "winged" it, not having a source of reference.
The first person I read for was memorable because she was my junior high school English teacher. She knew I did card readings but wanted a tea-leaf reading. I was dubious, but she said if I could read cards (a regular deck of playing cards at the time), then I should be able to read tea leaves. Since I had great regard for her I went along with it. She was amazed at the results--I was very young & knew little of man-woman relationships, but I told her what I saw.
The mechanics or ritual involved varies according to the reader as most of the divinatory arts, but there are some basics that are followed:
A teacup of the traditional shape (bowl-shaped) with a handle, set atop a saucer.
A spoon.
Loose tea. (I prefer black tea for the variety of shapes of its tealeaves.)
Boiling water.
The tea cup must have a bowl-shaped bottom & a handle. The shape is so the tea leaves may meander freely & also stick to the sides. (Those cups or mugs shaped otherwise do not lend themselves to this.) The handle is used as a reference point, where the readng begins.
The amount of loose tea recommended is a pinch or a half teaspoon. Too little will not produce results & too much will result in tea clumping together. The loose tea is placed in the cup by either the querent (the idea is for the querent to impart his energy to the tea) or the reader. Boiling water is then poured into the cup & the tea is permitted to brew in front of the querent. The querent focusses on the question or matter & may also stir the tea. When the tea is sufficiently cooled to drink, the tea is drunk until about a tablespoon is left in the cup. The physical contact of the querent is important so the cup should remain in the possession of the querent throughout the proceedings.
The querent then swirls the cup three times & immediately turn the cup upside down onto the saucer. Let the remaining liquid drain, & the querent turns the cup right-side up. The pattern of leaves in the cup are read, & some also read the pattern of leaves in the saucer, if any.