The 12 signs are the basic building blocks of astrology. Each sign has an association with both an element and a modality. Understanding these will give you a baseline understanding of key concepts that repeat throughout astrology.

Fire	Earth	Air	Water
Aries	Taurus	Gemini	Cancer
Leo	Virgo	Libra	Scorpio
Sagittarius	Capricorn	Aquarius	Pisces

Signs & Elements

12 signs in the zodiac can be broken down into 4 classical elements See table below. 

Each element possesses unique qualities: 

Fire: Action, creativity, boldness, passion

Earth: Stability, practicality, sensuality, realism

Air: Intelligence, objectivity, communication, technology

Water: Intuition, emotions, compassion, nurturing

Signs & Modality

Another way to group the 12 signs is by their modality. Modality refers to the way each group of sign expresses their elemental nature. These modalities correspond with a point in each season: beginning, middle, and end.  See tables below.

Modality	Point in Season	Concepts
Cardinal	Beginning	Beginning, initiating, directing
Fixed	Middle	Stabilizing, steady, secure
Mutable	End	Changeable, flexible, open to shifts, responsive

Cardinal	Fixed	Mutable
Aries	Taurus	Gemini
Cancer	Leo	Virgo
Libra	Scorpio	Sagittarius
Capricorn	Aquarius	Pisces

Signs by Element & Modality

Element and modality combine to assign each sign a unique way of being and expressing. With each season of the year, 3 signs occur in all 3 of the modalities. The point in the season during which the sun begins its transit of each astrological sign determines its modality. See table below.

Season	Beginning	Middle	End
Spring	Aries: Cardinal Fire	Taurus: Fixed Earth	Gemini: Mutable Air
Summer	Cancer: Cardinal Water	Leo: Fixed Fire	Virgo: Mutable Earth
Fall	Libra: Cardinal Air	Scorpio: Fixed Water	Sagittarius: Mutable Fire
Winter	Capricorn: Cardinal Earth	Aquarius: Fixed Air	Pisces: Mutable Water

Combining the concepts of element and modality is the basic recipe for assigning qualities to each sign. 

For example: 

Spring begins on the Equinox which also marks the first day of the sun transiting the cardinal fire sign of Aries. Aries is a passionate, bold sign (fire) which is associated with initiating ideas, projects, and endeavors (cardinal). The combined boldness and drive to begin new things makes Aries a natural leader.