NB: This article is not meant as a guide to using a cane. If you are sighted, using a cane in public is probably a bit illegal. If you have a vision impairment, see an O&M instructor.
There are two main types of white cane, used for different purposes. There is some variation in both and they can either be straight or collapsible. The first is the ID cane, a rod made of lightweight and durable material about the diameter of an index finger, about one meter in length and usually with a few inches of red at one end. Using the ID cane is simple - hold the cane in one hand at the middle diagonally across your body so that it can be seen from in front, at the side and behind. The cane is not meant to touch the ground, rather, it sends a signal to others that the user has low vision. It may also help to avoid large obstacles, such as poles, cars, people etc. It might signal to buses to stop even without signal, for drivers to take extra caution and for pedestrians to take initiative in avoiding the user in crowds.
The second major type of cane is the mobility cane, probably more common in public imagination. The cane has a handle on one end and a tip on the other. The puropse of this cane is also to identify the user as blind or vision impaired. More importantly, it allows the user to sense changes in surface material, potholes and bumps, stairs and curbs. Because the cane comes in contact with the ground it must much more durable and as such is usually made of tougher material than an ID cane. It is about the diameter of your thumb and should at minimum be at the height of your sternum. Some people prefer a longer cane that can come as high as the eyebrows. At any length, the cane should be able to reach two steps ahead of your feet. The tip is made of durable plastic and can be differently shaped for different purposes and terrains. Some are cylindrical, some are ball shaped and some can spin independantly of the rest of the cane.
When walking, hold the cane at the handle with your index finger pointing down towards the shaft. Tour hand should be at waist height and your palm facing left if right handed and right if left handed. At every step the cane tip should tap on the opposite side of the stepping foot and be two steps in front and roughly two inches to the side of each shoulder. It is vitally important that whenever the person moves, the cane is in rhythm. As the cane user improves, this rhythm should become gradually easier to maintain. Some visually impaired people, such as myseld, instead of tapping, glide the cane to detect smaller obstacles such as cracks or bumps in the pavement.
When ascending or desending stairs the cane first comes into contact with the first stair, trails up or down and subsequently is two or three steps ahead of the user. Stairs and other changes in terrain often have tactile ground surface indicators (TGSIs) to help detection, but some are placed with ignorance and inconsistency.
To help with walking in straight lines, a cane user uses indications on the ground or a wall to orientate them. These are called shorelines and can be the edge of a path, whether grass or a curb, a wall or a handrail. Apart from the cane a blind person uses hearing to distinguish all sorts of changes in environment. Open and close spaces sound different, as do varying traffic and pedestrians. Changes in surfaces can be detected not only with touch, but by changes in the sound of a step or tap. Over time, people develop landmarks, whether by touch, sound or smell that help them navigate.
Further reading: https://nfb.org/images/nfb/publications/fr/fr15/issue1/f1501tc1.html