Clairvoyance is the ability of "clear sight", in which a person sees images, colors, symbols, etc. This skill is experienced differently by different people.
Some people see the auras of others, or colors relating to emotions, etc. Some see symbols, which can mean different things to different clairvoyants. Some see images like a photo, a brief flash, or a rapid series. The more important things will stand out, whether they seem 'bolder' or are accompanied by a strong feeling.
Clairaudience is the ability in which a person hears voices. This can be a little confusing, as we often associate sound with the ears, whereas clairaudience happens as sounds within the brain. It is said communication comes through as energy vibrations that the human ears don't pick up, similar to the effect of a dog whistle.
It's said that those developing the skill of clairaudience will often feel tingling in an ear or on the side of the face. Sometimes they will hear tones, static, or something similar to a faint radio signal, or someone talking through a tin can. As the skill is developed further, these static noises will drop, and sounds will become clearer.
Clairsentience is the ability to feel and interpret the feelings of others, and people who can do this are called empaths. It is thought that many healers have this skill, as it helps them sense emotional and spiritual issues.
Very sensitive empaths sometimes tend to take on the symptoms and emotions of others. Being around negative people and large crowds can be incredibly taxing on them, and it's important that they take a moment to realize the true nature of what they're feeling in order to keep this in control.