Scrying is one of my favorite methods of divination. You can do it practically anywhere without needing any kind of special equipment. Like most activities, spiritual and otherwise, it takes practice, but it doesn't require special training, just focus and concentration.
What is scrying? My favorite definition is one given to me by one of my spiritual teachers: looking to see what's there. "What's there" is whatever impressions you receive when gazing at a surface or substance. Crystal balls are the classic scrying medium, but you don't have to be a Professor Trelawney style fortune teller to use one. You can also scry in a dark bowl full of water, a glass of wine, a fire or flame, a mirror (silver or black), smoke, moving water (rivers, ocean waves), clouds, and even the grain of a knotty piece of wood.
How is it done? Ideally, you'll be in a setting where you won't be disturbed or distracted by phones, people, pets, and so on. When you're first starting out, dark surroundings can help you focus on your scrying surface so you won't be visually distracted by other objects. Scrying outdoors at night in a campfire fits the bill, as does scrying indoors in the flame of a candle that's the only light in the room. Speaking of candles as the only light in the room, that's a good way to set up for scrying in mirrors, bowls of water, crystal balls, and similar objects. Just make sure the candle is positioned so the flame doesn't reflect on the surface.
Most books and blogs will give you the basic instructions to begin scrying: Set up your surroundings and your scrying medium. Ensure peace and quiet. Use your preferred method to reach a meditative state. Then look and see what's there.
For some people, that's all you need to do. You'll see images or receive impressions (sensory, thought, emotion) of whatever subject or situation you're scrying about.
But not everyone can "get there" so easily. What about the rest of us?
Here's the explanation and the tip that I give my students: In a sense, the surface or substance you're scrying in is a doorway to the Otherworld. Many ancient cultures viewed deep water of any sort as a gateway to the Underworld. It's these "other" places where you can find the information you're looking for when you scry.
So how can you look into The Other? Well, if it's just beyond Here, then that's where you look: just beyond the surface. If you're looking into a mirror or a bowl of water, focus your eyes below the surface - pretend you're looking into a swimming pool or a pond to see what's down at the bottom. If you're looking at something opaque like a flame, focus your eyes beyond it, as if you were looking right through it with x-ray vision.
This can feel very uncomfortable at first because it's not "normal." We spend our lives looking at the surfaces of things; looking inside or beyond is different and can feel awkward and wrong. Do it anyway. It may take some practice, but eventually you'll discover a whole new way of seeing.
Then you can look and see what's really there.