Divination is all about the process of trying to learn more about the universe than there is that meets the eye. When you have that curiosity to find out more about a situation, there is a belief that powers that are beyond the realm of the known world can help you understand what is happening and why. The belief is based around the ancient principles or techniques of trying to answer questions by using different rituals as a way of finding patterns.
Throughout history, divination has been seen as a systematic approach to decipher things that are happening all around us. Human beings, as a species, have constantly searched for answers about the unknown, trying to find out what is happening around them in a bid to become more comfortable and sure of their surroundings. Divination is just one of the ways that people have tried to answer those questions about the unknown, just like astrology, palmistry or tarot card reading.
The Past and Present of Divination
Since the times of the ancient Greeks do we have evidence that divination was practiced by the seers and oracles in the community. Whether it goes further back, maybe even to the times when humans lived in caves, we do not know but of the Greeks, there is massive evidence to support the claims of Oracles to be channels of communication between the priests and the Gods. However, Oracles were always in short-supply in Greece and were also not accessible to everyone in the community. That led to the rise of seers, a group of people who claimed that they were able to interpret the signs provided by the gods.
Seers would not speak directly to the gods but had the ability to use different signs, like the flight of birds or the patterns of wind to determine what their will was. There were no qualifications to become a seer and anyone who thought they could predict the future by looking at anything, even the orientation of a few sea shells thrown onto the floor, would become seers. Seers, however, could only answer questions with a "yes" or "no". Oracles, on the other hand, had a wider range of questions they could answer and didn't have to perform animal sacrifices, like seers.
The power and influence of these seers and oracles was so pronounced that their traditions and practices still continue today, despite all the technological advances. Today, those who claim to be involved in divination are still jumping through the same hoops despite knowing the fact that seers were known to manipulate the public to benefit their own selves. The Mesoamerican form of life is also known to be involved with a number of similar divination techniques involving Aztec gods and sorcery or magic was often used as part of the process.
Different Kinds of Divination
Divination has been a part of all cultures in human history, at some point of time or the other. There are techniques and principles that have been found to exist in more than one culture, even those that are completely unrelated to each other. Mantia is a term that was coined to define the kind of mystical or prophetic roles of these future-watchers and the kind of tools they would use would become a part of that description as well.
For e.g. Necromancy become the term to define the study of divination using the dead remains of human beings while Aeromancy was about studying the patterns of the wind and figuring out what lay ahead in store. Geomancy or Feng Shui was considered as the art of reading the lay of the Earth or the markings on it to determine the future while something like Enochian Chess, a game of chess that was a four-player version instead of the regular two-player concept, was also a mode of study. There are some modern forms as well, such as Megapolisomancy, which is the study of the future through the presence of large cities, or Tasseography, which is about interpreting the future through tea leaf reading or tarot card reading or even reading sediments of wine.
In general, you can either indulge your divination hobby in the field of Omens, Cleromancy, Augury or any spontaneous form. Omens are about recording of sequences of unusual events to predict some future phenomenon that might occur as a result. For e.g. the strange birth of a cow's calf might be interpreted as the onset of famine, in some cultures. Cleromancy is about casting a group of the same kind of objects, like sticks or bones, and then looking at the pattern they fall in to determine the future.
Augury, while maybe not as popular today, is about sacrificing live animals and studying the shape of the livers of those animals. Nowadays, it is still a study of shape or distances, but maybe not involving the sacrifice of live animals. Dowsing is often used as a technique, as is the flight patterns of birds, in this study but if everything else fails, there is always the idea of making something spontaneously from something you see, and labelling it as divination. You can use anything in that case - from things you see or things you don't.
Techniques for divination have been as varied as the people who use them and there is no known format of study for the people who are involved in it. If you are looking for something in this arena, make sure you study that technique well and stay away from sacrificing anything for the purpose of predicting the future. Divination can also be a great party trick and if you've got friends and family coming over, you have a fantastic ice-breaker in the form of the ancient art of divination!