Sun - your ego, your external personality summed up. Warm, welcoming, popular, generous, confident or insecure. Think of Leo.
Moon - your internal personality, your deepest feelings and emotions. Nurturing, motherly, passive, emotional. Think of Cancer.
Mars - your aggressive tendencies, strength, go-getter attitude, sexual desires. Choleric, fiery, active. Think of Aries (to a certain extent Scorpio).
Venus - where you see beauty and love. Indulgent, romantic, attractive. Think of Taurus or Libra.
Mercury - your thought process and its expression. Punctual, unstable, quick, witty. Think of Gemini and Virgo.
Jupiter - your higher learning and success. Ever-changing, expanding whatever it touches. Think of Sagittarius (or Pisces).
Saturn - your biggest challenge, your teacher. Commanding, restrictive, organized, rewarding. Think of Capricorn (and to some extent of Aquarius).
Uranus - your rebellion and humanitarian efforts. Always going against the norm, detached, intellectual and helpful. Think of Aquarius.
Neptune - your illusion, dreams and subconsciousness. Glamorous, meditative, delirious. Hard to grasp. Think of Pisces.
Pluto - your obsessive tendencies. Possessive and controlling, powerful and dark. Represents death, destruction and rebirth. Think of Scorpio.