The 12 signs are further separated into four elements, namely FIRE, EARTH, AIR and WATER. By examining the different planets in these signs together with their Qualities, astrologers can draw a more in-depth profile of a subject. 

FIRE -- Aries, Leo. Sagittarius. People of Fire signs are explosive, volatile, energetic. They are leaders, inventors and adventurers. Their weaknesses are their tendency to work to extremes and burn themselves out. Fire attributes are best counterbalanced by the Earth signs.

EARTH -- Taurus, Virgo, Capricorn. People of Earth signs are practical, cautious and reliable. They generally lack imagination and creativity. 

AIR -- Gemini, Libra, Aquarius. Air signs denote intellectual activity, thought and philosophy. People who possess many planets in the Air signs are good planners. Those without Air signs may have difficulty in communication or expressing themselves artistically. An excess of planets in Air signs is best counterbalanced by Water signs. 

WATER -- Cancer, Scorpio, Pisces. Those with planets in the Water sign moderate the practicality of Earth, the ideas of Air and the careless energy of Fire. Having many planets in the Fire sign usually indicates a person is lively, emotional and enthusiastic. 

Although this interpretation is simplistic and direct, astrologers must also consider the effect of the Qualities and Aspects of the subject's birth chart to draw a complete personality profile.