The elements divide the zodiac into three. Signs in the same element are in trine aspect. These determine the manner in which we perceive the planet.
The fire signs are Aries, Leo and Sagittarius.
Fire is optimistic, future oriented, visionary. It has some difficulty with dealing with routine and boredom.
The earth signs are Taurus, Virgo and Capricorn.
Earth is practical and wants to be useful. Due to the application and diligence there can be a lack of spontaneity and creativity.
The air signs are Gemini, Libra and Aquarius.
Air is concerned with communication, mental faculties, and objectivity.
The water signs are Cancer, Scorpio and Pisces.
Water is must be contained within a container or it leaks away. Water is concerned with non-verbal and emotional expression. It is essentially subjective.