Everything in astrology is tied to something, just as nothing in life can be understood in isolation. A good way to begin understanding anything in life is to contrast and compare -- consider what it is not which can help you learn what it is. In that spirit, I've briefly outlined the differences between opposing signs. While each sign needs to do things the way they were meant to, each can teach the other something about how to deal with their shadowed side traits.
Aries/Libra
Aries has a certain fiery 'go for it' need. It needs confrontation and utilizes direct methods of dealing with things and people. Aries is not about carefulness or taking things slow, thinking things through. Being a fire sign, it's about action. Aries has a need to focus on self. Libra has a need for peacekeeping, for gentility, not the fire and uproar that Aries thrives on. Libra utilizes tact and diplomacy to compromise with others. Libra has a need to focus on the dynamic of a partnership, by understanding and being interested in the needs of the other person, seeing things from their point of view. This allows Libra to gain balance and an inner harmony. Libra can teach Aries to think things through before impulsively taking steps that may turn out to be destructive and hurtful. Aries can teach Libra how to take action when Libra becomes too indecisive to go forward.
Taurus/Scorpio
Taurus has a need for simplicity and calm. It has a measured approach to life and an understanding of life's natural, unfolding rhythm. To Taurus, common sense is enough to navigate life's highs and lows. Scorpio has a need for depth and introspection. Scorpio is not satisfied with a simple, surface answer; it knows that what you see is generally not the whole story, the real story. Scorpio thrives on change -- though it is a fixed sign and not constantly in motion such as a mutable or cardinal sign may be, it overturns itself often -- the phoenix from the ashes. Taurus has a need for stability and a slow building over time, so a fiery death and rebirth is not its speed. Scorpio can teach Taurus to avoid oversimplifying and falling asleep. Taurus can teach Scorpio to come up from the dark once in a while and see that not everything is a complicated conspiracy!
Gemini/Sagittarius
Gemini has a need for knowledge of all kinds, little stuff, big stuff, facts, hearsay, all of it! Gemini needs to learn the who what where why when of the story. Gemini likes the learning as much as the knowing, and likes to share what it's learned, gaining new perspectives and new information each time the info changes hands. Sagittarius also has a need for knowledge, but it does something different with it. It wants to see the bigger picture -- meaning and philosophy, and how all the information we gather fits together. Sagittarius tends to gather meaning by experience and Gemini tends to gather data in snippets of information read or heard, but this is not always the case for either of them. Gemini can teach Sagittarius to open up to all ideas, even if some of them are contradictory and don't fit into the set philosophy Sagittarius may have decided upon -- that truth is fluid and complex. Sagittarius can teach Gemini that all the crazy to and fro motion of gathering snippets of unrelated data has no purpose if all it does is fry one's brain and has no meaning!
Cancer/Capricorn
Cancer, being a water sign, is comfortable with the fluidity of emotion and its ups and downs. Cancer has a need to delve into itself, to act from its center, its heart. Cancer understands that the heart is what needs to govern the body and mind and its tools are love and a caring nature. Cancer works well with a network of loved ones all caring for each other. Capricorn has a need to follow its intentions over its emotions. Its tools are its ability to act according to the bigger picture and its responsibilities. Capricorn sets goals and then works toward achieving them, sometimes denying temporary whims in order to not stray from its path. Capricorn prefers solitude and self-reliance in life. Cancer can teach Capricorn that directing one's emotions does not mean shutting them out entirely and becoming frozen and robotic. Capricorn can teach Cancer to bring order to its internal emotional chaos and to embrace more selfdependence and less codependence.
Leo/Aquarius
Leo has a need to engage fully with life. Being a fire sign, it must leap into life and announce its presence. Everything inside of Leo must be expressed outside. Leo is a performer at heart and lights up when its performance appreciated by people. At its best, Leo is as playful, joyous, and generous as a child. Aquarius has a need to express itself also, but while Leo likes a crowd's approving feedback, Aquarius needs to turn away from the crowd when it asks Aquarius to be something other than its most authentic self. Aquarius also has social needs and interests, but they are likely to be loftier than Leo's, such as a desire and concern for everyone's rights -- especially everyone's right to be themselves. Leo can teach Aquarius to lighten up and not be so detached from life and from people; that it's ok to belong and want to belong. Aquarius can teach Leo not to pander to the audience so much that you lose your ability to express your true self, even if the audience doesn't applaud.
Virgo/Pisces
Virgo is looking for, creating, and attracted to order in various ways. It is not just about cleanliness or obsession as some cartoons of Virgos depict, but about efficiency and perfection. Virgo, an earth sign, utilizes tools of practicality and critical thinking. Virgo uses a narrowing and detailed approach to achieve perfection in whatever she does. Virgo appreciates a well developed and useful skill and needs to feel useful in a practical, tangible way. She understands the world through analysis and reasoning. Pisces understands the world through intuition and vision. Pisces utilizes the tools of acceptance and compassion. It has an open and flowing energy. Pisces understands wholeness; the interconnectedness of all beings, and how a shared reality is an illusion -- there are many worlds contained in one and many possibilities.
While Virgo seeks to define, discern, and separate through creating boundaries, Pisces seeks to open up, to connect to the spirit of others and to share itself. Pisces understands that the whole is greater than the sum of its parts, whereas Virgo seeks to understand the parts, to get down to the details. Virgo can learn compassion, patience and a more faith oriented understanding from Pisces, else Virgo's critiquing turn to cruel dissection. There are many ways of understanding something that don't respond to the scientific method and a graph! Pisces' optimism needs Virgo's methods action and reality in order for hope and faith to not become avoidance and delusion. Virgo is about definitions but sometimes Pisces doesn't know where to draw its needed lines. Pisces can learn from Virgo not to drown in their compassion too much so that they cannot differentiate where their responsibility ends and another's begins, especially when it comes to Pisces' own needs.