The dictionary meaning of divination:
The art or act of foretelling future events or revealing occult knowledge by means of augury or a supernatural agency.
The word Divination comes from Latin divinare "to foresee", related to divinus, divine) it is the attempt to gain insight into a question or situation by way of a process or ritual. Interpretations of how a querent should proceed are gained by reading signs, events, or omens, or through contact with spirit guides.
I believe it is an integral part of witchcraft and it has been used in various forms for thousands of years.
There are many, many forms of divination.
Tarot - probably the best known and one of my personal favourites is the art of tarot reading, gaining insight into a situation by understanding the individual tarot cards drawn in a reading. Similar to tarot are oracle cards. The official title for divination using cards is Cartomancy.
Crystal ball - a crystal ball with inclusions (imperfections) works best for me, and with a lit candle beside the ball to help cast images.
Scrying – this can be done using a bowl with a dark inner, fill with water and drop a silver coin in the bottom, then see what images come to you. This can also be done with a bowl of water, ask your question, then sprinkle herbs or drops of ink onto the surface of the water to gain images for an answer. Using moonlight reflected onto the surface of water works well too. This can also be done with a scrying mirror – a mirror that has a black surface.
Pendulum – another one of my favourites. You can buy all sorts of beautiful crystal pendulums, but it is also easy to make your own – a holey stone on a string, a small piece of wood or an anise seed on the end of a thread works well too. Ask standard questions first – ‘give me a yes, give me a no’ to see which way it swings, then ask your question.
Pyromancy – the art of divination through fire. This can be done by reading the signs in the flames of a bonfire, a fire in your fireplace, or even with the flame of a candle. If you have a bonfire, wait until it dies down to the hot embers then throw a handful of salt on and see what images you get.
Runes – divination using a set of rune stones, each marked with a symbol from the runic alphabet.
Astrology – we should all know this one! Divination using celestial bodies – the sun, moon, planets and stars.
Also one I like to do – Crystallomancy – the art of divination through crystal gazing, this works best with a crystal that has lots of inclusions.
Palmistry – divination through the interpretation of lines and structures of the hands.
Tasseography – reading the tea leaves!
Aeromancy – divination from the air and sky, particularly the shapes of clouds.
Augury – the general description given to divination by interpreting signs and omens.
Capnomancy – divination by reading the smoke rising from a fire.
Lithomancy – divination using stones (similar to runes but without any symbols on)
Oneiromancy is interpreting dreams.
There are literally hundreds of forms of divination, all with perculiar names, however one that I found but have not tried yet is Tiromancy which is a type of divination using …. Cheese!