Below are ten symbols you would commonly see used on witches stones. Personally these are the symbols I would use if putting together a set for someone who was interested in learning them.
Wyrd - Fate, destiny, the unknown, that which is yet to be decided.
Black - Negativity, bad luck.
Spears - An argument, dispute or confrontation.
Moon - A change, usually within 28 days (one moon cycle).
Sun - Growth, prosperity, abundance.
God - A man or a leader like/providing force.
Goddess - A female figure, a protective force or a care giver.
Birds - A message.
Corn - A work or career situation, or hard work bringing rewards.
Rings - A partnership or relationship.
Some other symbols you may come across are;
Spiral - A situation gathering momentum, a situation that has been ongoing for some time.
Birds - A message.
Waves - Travel, contact from close friends/family.
Wheel - The current situation is only temporary.
Nail - Needed help/protection coming.
Key - A new opportunity presenting itself.
Usually to use the stones I would do either a three or seven stone casting. Three stone castings are good for getting a feel for the stones when you first start working with them, they are also great for quick answers and readings to uncomplicated questions and scenarios. Seven stone castings are great for general readings, or more complicated queries. Both are performed pretty much the same way.
First hold the bag containing the stones and gently shake the stones whilst clearly holding the information and answers you wish to get from the reading in your mind. If doing the reading for someone else make sure you have this person at the forefront of your thoughts too.
Pick stones out of the bag , hold them together in one had 4-6 inches above table and then drop them. Look at the stones and how they have landed. Some stones will have fallen close to each other , these stones will relate to each other. Some stones may have landed upside down. Some readers will simply turn them over and read as normal - (this is my own chosen method), some will discount them all together, and some believe that it indicates the opposite of the meaning indicated when the stone is the correct way up."