Geomancy interests me because I especially like rocks, stones, and even pebbles (rocks you can hold in your hand or put in your pocket). Stone is like a hard, cold fact with a very long history, by our human standards. You can find rocks, or stones, in a lot of good places: the beach, the forest, the side of the road. You know, you've seen them. I don't pick up rocks/stones which belong somewhere, like someone's yard. Is it silly to feel they have a home there and shouldn't be taken? Maybe, but that's how I feel.
I haven't tried geomancy in an official way, not to read the future. I just enjoy stones. I keep them around, in my bedroom (give them a little clean up if you bring them indoors), outside in the yard and the garden we have a lot of rocks. They make great pets, if you feel the need for dependable companionship with few needs, like grooming or feeding. You can make a little house for them, if you like. I like just having a few good rocks around.
At most, I use a stone to point me in a new direction. Just warm it up in your hand for a bit and see where it falls as you turn around (slowly, give the stone a little time and don't make yourself dizzy).
You could find other ways to use stones as a do-it-yourself divination. I think you need to have some connection to the stones, at least liking them for their history, their shape, colour, usefulness, connection to the Earth... something. Otherwise you may as well be completely random. I think divination works due to at least some belief in fate. Some idea that outside things can influence you, the world in general.
Geomancy is divination using stones. I find most divination has a lot of rules but essentially the whole thing is about how you feel looking at the cards, entrails (not for me) rocks, etc. At least that's what it used to be. People do have a way of taking something simple and making it a huge complicated knot they can make some money out of.
A system of divination that employs the scattering of pebbles, grains of sand, or seeds on the earth and then the interpretation of their shape and position.
I especially like this description, from The Mystica site. The site has been taken over and just posts click bait now. No sign of the original post I read this from.
Geomancers are spiritual ecologists. (Found on a group no longer online).
It's not feng shui, and it doesn't have anything to do with ley lines or dowsing. It's been called earth astrology, a Western equivalent of the I Ching, and the forgotten oracle of the Western world. It was one of the most popular systems of divination in the Middle Ages and Renaissance, and stands at the center of traditions of magic, philosophy, and initiation deeply relevant to today. What is it? Geomancy.
Geomancy is a traditional art of divination that uses the sixteen geomantic figures – patterns of single and double dots – to explore the mysteries of past, present and future. As a branch of the Hermetic tradition, an ancient Western system of spiritual transformation and magical philosophy and practice, it relies on the fundamental Hermetic law, the unity of the macrocosm (the universe around us) and the microcosm (the universe within us) to open up hidden potentials for knowledge, wisdom, and power and, in the words of the legendary Hermes Trismegistus, “perform the miracles of the One Thing.”
Quote Source - Collegium Geomanticum
Geomancy, a compound of Greek roots denoting "earth divination", was originally used to mean methods of divination that interpret geographic features, markings on the ground, or the patterns formed by soil, rocks, or sand. Its definition has expanded over time (along with the recognized definition of the suffix -mancy), to include any spiritual, metaphysical, or pseudoscientific practice that is related to the Earth. In recent times the term has been applied to a wide range of other occult and fringe activities, including Earth mysteries and the introduction of ley lines and Bau-Biologie [de].
Geomancy was a common, and cross cultural, forms of divination in premodern times. In regards to Africa and Europe, it was considered a forbidden practice by various Christians and Muslims across the medieval era. In other regions and cultures, geomancy practices include Sikidy and Ifá (found in Africa), I Ching and Feng shui (found in China), Kumalak (found in parts of Central Asia), Vastu shastra (in India), Kahuna kuhikuhipu'uone (in Ancient Hawai'i).
Quoted from Wikipedia.
All of that should give you a starting point, if you want to learn more about the 'rules' for geomancy as a method of divination. Or, you can just enjoy having more rocks around.