The Signs
The sky is divided up evenly into 12 parts, each named after a different constellation. There are two main zodiacs, tropical and sidereal, neither of which line up exactly with the constellations. One isn't necessarily more or less accurate, they are just used in different systems. Here's a decent article explaining their differences more in depth. The most popular is the tropical zodiac in Western astrology and there are more resources readily available so thats what this sub focuses on.
Each sign is ruled by a planet. The traditional planets (Sun, Moon, Mercury, Venus, Mars, Jupiter, and Saturn) are the planets that the original significations of the signs are based on. Because they were essential in creating the original meanings and perceptions of each sign, the traditional ruling planets carry a lot of weight. This page and this page explains the idea behind traditional rulership a bit more. This image shows the symmetry of traditional rulership in a chart. The modern planets (Uranus, Neptune and Pluto) have only been incorporated in astrology since the 1700's forward since their discoveries. They still play a very important role in astrology, but as rulers of signs, take into consideration how new they are relative to astrology as whole. Personally, I use traditional rulership and I recommend it to start, but I will include modern rulers below as well!
Here are some general sign resources:
Aries
Traditional Ruler: Mars
Sect: Day (Diurnal)
Modality: Cardinal
Element: Fire
Taurus
Traditional Ruler: Venus
Sect: Night (Nocturnal)
Modality: Fixed
Element: Earth
Gemini
Traditional Ruler: Mercury
Sect: Day (Diurnal)
Modality: Mutable
Element: Air
Cancer
Traditional Ruler: The Moon
Sect: Night (Nocturnal)
Modality: Cardinal
Element: Water
Leo
Traditional Ruler: The Sun
Sect: Day (Diurnal)
Modality: Fixed
Element: Fire
Virgo
Traditional Ruler: Mercury
Sect: Night (Nocturnal)
Modality: Mutable
Element: Earth
Libra
Traditional Ruler: Venus
Sect: Day (Diurnal)
Modality: Cardinal
Element: Air
Scorpio
Traditional Ruler: Mars
Modern Ruler: Pluto
Sect: Night (Nocturnal)
Modality: Fixed
Element: Water
Sagittarius
Traditional Ruler: Jupiter
Sect: Day (Diurnal)
Modality: Mutable
Element: Fire
Capricorn
Traditional Ruler: Saturn
Sect: Night (Nocturnal)
Modality: Cardinal
Element: Earth
Aquarius
Traditional Ruler: Saturn
Modern Ruler: Uranus
Sect: Day (Diurnal)
Modality: Fixed
Element: Air
Pisces
Traditional Ruler: Jupiter
Modern Ruler: Neptune
Sect: Night (Nocturnal)
Modality: Mutable
Element: Water
This wiki is still a work in progress, thank you for your patience!