The first and most basic practical division is to divide the zodiac into 2 genders or sexes also known as masculine and feminine, positive and negative, extroverted and introverted, etc. This duality or polarity is the most fundamental law or principle of nature and alternates around the zodiacal wheel keeping it in perfect balance.

The masculine gender expresses in two basic ways in astrology: through the high masculine fire signs and through the low masculine air signs. The feminine gender expresses through the low feminine earth signs and the high feminine water signs. Both the air and earth signs are close to being bisexual but not quite.

The three modes or quadruplicities are the next most basic division dividing the signs into three camps; cardinal or active, fixed or unmoving, and mutable or changing. The main definition of each group is always summarized by the the first member of that group. Just as Aries underlies all the signs giving them life, so Aries underlies all masculine signs giving them force, and Taurus underlies all feminine signs giving them receptivity. Likewise, Aries underlies all cardinal signs making them starters, and Taurus underlies all fixed signs making them stubborn, and Gemini underlies all mutable signs making them changeable or adaptable. Its the same with all the other remaining divisions.

The four elements are the next major grouping division on the wheel with Aries underlying the fire signs making them all active and inspirational, Taurus underlying the earth signs making them all practical and productive, Gemini underlying the air signs making them all communicative and intellectual, and Cancer underlying all the water signs making them all emotional and intuitive. The water signs are actually the night or lower expressions of the fire signs wheareas the air signs are the day or higher expressions of the earth signs. This is evidenced in the dual rulership scheme.

The final major division is the six oppositions or polarities, with Aries underlying itself and Libra as the axis of identity(me vs you, or self vs others). Taurus underlies itself and Scorpio as the axis of resource(mine vs yours), Gemini underlies itself and Sagittarius as the axis of ideas(my ideas and your ideas), Cancer undelies itself and Capricorn as the axis of security(private vs public security), Leo underlies itself and Aquarius as the axis of love(personal vs group love), and Virgo underlies itself and Pisces as the axis of service (material vs psychic or immaterial service). Opposite signs are two different sides of the same coin.

There is another way to group the twelve signs that is less talked about. This is the linear division rather than the circular or geometric one. The bottom diagram clarifies this...

There are also six basic different divisions here beginning with the signs as a whole which signify the creation or god expression as a whole. Everything imaginable is covered by these twelve signs as one. It is total unity and completion from which we came and shall return to.

The first practical division is the first six signs which represent self and objectivity versus the last six signs which represent the not-self and subjectivity. People with most of their planets in the first six signs have greater sense of self(Aries) and personal direction whereas those with most of their planets in the last six signs are more geared towards co-operation(Libra) and the larger picture. The subjectives look to the objectives for guidance and direction while the objectives count on the subjectives for strength and decisiveness.

The next practical linear division is thre first, middle, and last four signs known as the primal, individual, and universal groups. The primal signs from Aries to Cancer is mostly cardinal and are more concerned with basic primal needs and will act to satisfy those needs. The indiviudual signs from Leo to Scorpio contain more fixed signs and are more concerned with social status, personal belongings, and expression through others. The Universal signs from Sagittarius to Pisces contain more mutable signs and are more concerned with higher ideas or principles and seeing the larger picture.

The next division is in groups of three signs each, after the seasons of the year. Aries, Taurus and Gemini are the spring signs when life is budding, and represent youth. Cancer, Leo, and Virgo are the summer signs when it is hottest(at least in the more populated northern hemisphere), and represent adulthood. Libra, Scorpio, and Sagittarius are the autumn or fall signs and represent maturity and Capricorn, Aquarius, and Pisces are the winter signs and represent old age and death.

A fourth division is six binary pairs which are subdivisions of the primal, individual and universal groups and of which little is written about. Then there are the individual signs themselves which encapsulate twelve major expressions or themes in life. One can form more groupings and significations by combining any one or number of signs but these are the most basic.

And this is only the signs! It gets more complex when you bring in the planets as well, which are activators or vehicles for the signs, but it all starts with the signs, which is how most people learn about astrology.