Ever notice you have several friends who share the same Sun sign -- but it's a different sign than yours? It's only natural that we tend to befriend people whom we admire ... and with whom we feel a kinship.
How then does astrology come into play?
One's Sun, Another's Moon
The strongest connection between friends -- or lovers, for that matter -- is the conjunction of one person's Sun with the other's Moon sign. For example, if you're a Cancer with a Virgo Moon, you may connect well with someone who has a Virgo Sun. It's also likely that someone with a Cancer Moon will feel a connection to you.
What's at work here? Your conscious ego function is seeking a match that complements you on an emotional level. After all, nothing makes a friendship last like a strong emotional connection, when the two of you simply "get one another" on a level deeper than usual.
Another astrological theory that can come into play when making and keeping friends has to do with looking for signs 90 degrees ahead of yours. For example, if you're an Aries, you may unconsciously seek out Cancer friends; continuing this trend, Taurus seeks out Leo's companionship, Gemini seeks Virgo's, and so on.
This has to do with opposites attracting. Those "ahead" of you on the zodiac's path have a different set of skills and attributes from which you can learn. By pairing with them, you may endure a bit of a bumpy friendship at times, but one that's also full of growth and learning.
Fire Attracts Fire
Finally, here's a fairly simple, yet tried-and-true principle: Signs that share elements (Fire, Water, Earth, Air) generally mingle well with one another. For example, if you're an airy Libra, you'll likely make a strong connection with fellow Air signs Gemini and Aquarius; the same can be said if you're an earthy Virgo and other fiery types (Taurus or Capricorn).
By looking at your close friends and examining the signs you're most attracted to, you'll gain a better sense of the companions who comfort you!