There are four elements in Astrology.They are "Water","Earth","Wind","Fire". Pisces,Scorpio,Cancer
belong to Water. Taurus,Virgo,Capricorn belong to Earth. Gemini,Libra,Aquarius belong to Wind. Aries,Leo,Sagittarius belong to Fire.

I found some short introductions about each star sign from a site.


Fire:
1.Aries
Aries are pure and sincere in character.They are ambitious,never refusing hard work.Also, they are persist, always pursuing self-achievement.

2.Leo
Leo are passionate, like to show off,and possess charisma.They are excellent players of their career.Having aggressive nature and acting talent, they have excellent creativity.

3.Sagittarius
Among the twelve zodiac signs,Sagittarius have the most active power.When they are facing with situations,
where things are not completed as they suppose to be, they will be agitated.


Water:

1.Pisces
Pisces belong to the Water Sign,they have mild temper,easy going, generous, kind, and they are also quick thinkers.When their friends are in trouble,they will not sit aside and doing nothing.

2.Scorpio
Conservative,reserved,mysterious,confident,
energetic,sexually active...Maybe when you hear those characteristics, you will be awe-stricken by Scorpio.


3.Cancer
Cancer are full of motherly love, they can take very good care of their family.For they are very defensive, romantic in nature,sensible and sensitive.However, they are very picky,and like to fantasize.


Earth:

1.Taurus
Taurus have straight characteristic,yet they are more enthusiastic,and kind heart.And they like to help other people.They have clean definition for people or things, in terms of love or hate,they will not lose their focus.

2.Virgo
Virgo are sensitive, and very cautious in doing things, always searching for perfection, but sometimes they seem paranoid.

3.Capricorn
Capricorn are hard workers, often working too hard for their whole life.Capricorn have mild temper, even if others treat them like dirt,they still return with humbleness and respect.They are stable in nature,very self proclaim, and define right or wrong clearly.


Wind:

1.Gemini
Passionate, clever, and sociable,these are the general characters belong to Gemini.Gemini are very good at promoting themselves.However, Gemini have unstable characters, they can be described as double face.

2.Libra
The most notable characteristic of Libra, is their fairness and equalization in doing things, or else they will not know how to continue their works.Therefore, justice and righteous are the motto of Libra.

3.Aquarius
The Aquarius praise for freedom,have brilliant talent,
treat others well,smart and clever,and posses strong ego.


source:http://www.hi2ez.com.tw/2ezclass/default.htm