There are a few ways to tell if a ghost is near you. First, many people who have experienced seeing ghosts have said that they saw a ghost. The ghost according to them looked like a real person, but you could see straight through them. Also, if you were close enough to them, then your hand would go right through them. Another way people feel that a ghost is near them is by a cold feeling.
Sometimes, a person won’t see a ghost, but they know one is present because of a cold feeling in the room. Occasionally, an apparition will appear but it will not be in the form a human being, but a white shape will suddenly appear in the corner of the room.