Scrying or crystal gazing is to use  a crystal ball, a seer stone ,or other crystal as a divining tool . One seeks to receive  visions or information  about issues, the future, a present situation or  to foretell events , discover hidden knowledge , prophecy, or perception by  intuition and  instinctive foresight.

Traditional crystal  gazing is something I don't often do because it seems easier for me to  receive   information  by using  an imaginary ball or screen which I see in my mind or which appears before me .

Sometimes this occurs while I am holding a crystal. On the  occasions I have received information while crystal gazing, the information  has not appeared in the crystal but in front of my brow chakra or in my head . So to me the
crystal is like a meditation tool ,something that you use as a focus while you reach the mental openness  that allows you to perceive information .

Many people do see visions in the crystal. Some see or sense symbols, colors or shapes that they interpret. Other people actually see images or  events unfolding as though viewing  a movie.

The process of gazing is quite similar to other psychic reading and meditation techniques .
While tools may help with scrying, the knowledge and ability to do this work lies within the seeker rather than in the tools. Many people  have had visions and gotten information while holding a crystal  or gazing into a crystal but possibly  as many or more  have the same experiences without gazing into a crystal .

 Crystals are amplifiers and transmitters and receivers of energy. This gives them the capacity to assist seekers in scrying and other divination. The choice of a crystal scrying tool is entirely up to each individual. Some people prefer a clear crystal ball or a seer stone which is frosted on the outside with a clear polished internal center area. Others people prefer
crystals or crystal balls  with inclusions or rainbows which act as points of focus, These inclusions are often called doorways.  Some people use window crystals or place a crystal cluster in a bowl of water.  The clear or included quartz crystal is the most commonly used  scrying stone but other stones including  black or other  dark obsidian can also be used .

The process of learning to scry consistently can be a long one so patience is of importance.
While some people are able to scry as soon as they try, most people find that it may take several weeks of  of at least 20 minutes practice daily  before they begin to get results.

There are several different traditions of scrying. The principle differences are often in the set up  and lighting surrounding the crystal . The best lighting for beginners seems to be a dimly lit room. Neutral light, such as that of north light or an overcast day or twilight  is usually less distraction than brighter light. Some scryers prefer that light be behind them and over their shoulder . Others prefer to place a candle behind the crystal ball or other scrying  crystal.

You want to have your gazing crystal in a place where it is comfortable for you to gaze into it for quite a while. You do not want to have reflections of surrounding objects visible in  the crystal. If you have a light box you may find that placing your scrying tool on it is perfect as the crystal is completely  lit from beneath. If you do not have a light box  the crystal is often placed on a stand on a black or dark blue silk or velvet cloth or on a dark covered  pillow.

Your gazing  crystal may want to be cleared before and after each use by your preferred method. I recommend clearing with shakti from the Crystal Empowerments if you have been attuned to that system or a shakti from another energy system or with breath. Other clearing methods also work well if not as swiftly.   Clearing  crystal balls is more about removing influences from previous work than about  clearing the crystal itself.

Many crystal reader and scryers  prefer that they be the only person to touch their  gazing crystal because another person's energy might be absorbed by the crystal and effect readings . A few  scryers do have the querant ( person being read for)  hold the crystal  before reading. This is  in order to fine tune the crystal to that persons energy.

Most people probably try too hard when learning to scry. Their own effort  to see something in the crystal   interferes with the process.  Relax and allow yourself to be open to the experience. Begin by Communing with the crystal and grounding and centering  yourself. Connect with your high self and or spiritual source. Deep breathing can help with this connection. This will eliminate any possibility of contact by or with entities that might be considered hostile or negative.
This should not be a problem but should you have specific issues with protection or fear of psychic attack by all means surround yourself with a circle of light,  call in your angels or use a simple protective method of your choice before beginning.  I presume anyone reading this would never  seek contact and information from destructive entities. (energy follows attention).

Whatever gazing or other divination method is being used people get clearer  results when they have a clear reason for scrying. It  is good to have prepared  a question or questions or formed a clear intention to receive information about a particular  subject or situation rather than to read the crystal  just out of curiosity . 

Decide your intention and purpose for the reading , (which initially will probably just be to learn how to scry).  Gaze into the crystal with a soft visual focus and a mental openness.
This is just like a basic meditation when your attention wanders bring it back gently to focus on the center of the crystal.

 Gaze into the  ball, but do not stare. Some people suggest you try not to blink but blinking will not interfer with your reading. Do not focus on your blinking while you are gazing.  Just relax and gaze.  Most people do not get results the first time or first few times they sit with the crystal .
Eventually  you may notice a small cloudy  glow in the center of the crystal or in front of the crystal. This is the  focusing area where your visions will appear. Often beginning readers are so startled by the initial appearance of images or colors that they lose focus completely. When you practice persistently you learn how to maintain clear focus .

You might see easily understood  images but you may see clouds or colors or symbols.  Often it  helps to have a pen and paper at hand to keep a quick log of symbols or words and other impressions  Though not everyone can maintain focus and take notes .

There is no absolutely uniform system for interpreting the meaning of symbols and colored clouds. Dream books and color healing guides can have suggestions for traditional interpretations of symbols .  These tools help you awaken your intuition about the meaning of the patterns and images  you see. The degree of turbulence and movement in clouds may
indicate the intensity of the event referred to or its nearness in time .

There are traditions that many readers use. Here is one set of interpretations ,but it is not definitive, use your intuition .

 Blue clouds may symbolize success of career or business,
Gold clouds symbolize prosperity, steady cash flow and possibly new romance.
Gray/Dark gray or Black may symbolize sadness or ill fortune.
 Green clouds symbolize health, happiness .
Orange clouds may  symbolize hidden aggression and anger, or troubled emotions.
 Red clouds symbolize danger to come.
 Silver clouds symbolize troublesome times ahead followed by good  times.
White clouds symbolize very good fortune ahead.
Yellow clouds symbolize upcoming obstacles.

I recommend that if you have a set of color meanings and correspondences that you are already familiar with  see if those work for you in scrying  before you work at learning another system. There are quite a few books and web sites about crystal gazing and other scrying methods if you want to explore this area more thoroughly.