1. You will have to find an abandoned/empty house in the a quiet surroundings. No one should be living there for years. Probability to detect an activity on such a location is very high.
2. The best way to measure a paranormal activity is your mind itself. There are places where you feel saddened, bad feelings, sorrow thoughts, negativity. Those places are considered to be of a higher probability of having some paranormal presence.
3. EMF Meters (Electro Magnetic Field Meters) are used to measure a presence of any electric or magnetic field. Many modern day 'ghostbusters' use this device to conform a presence. But I have never used it.