In all of my beginner's Astrology teleconference classes, I teach my students how important it is to thoroughly analyze the Sun, Moon and Ascendant (or Rising sign) of any horoscope. You can find out your Sun, Moon and Rising Sign with an Essential Birth report, and even if you don't have access to anything else in the birth chart except for these three points, you can still gain amazing insight into anyone's personality potential. (And you can find more information about my teleconference classes here!)
The Sun sign represents your basic essence and vitality. It's how you experience your ego, and the traits in your Sun sign speak to qualities you're learning to embody.
The Moon sign represents your emotional nature and the feeling instinct. It's how you experience nourishment and safety. It's what you need to feel fulfilled.
The Ascendant is what I like to call the "cover of your book." It reveals the qualities you most visibly show to others upon first impression. While this cover is definitely not the entire story, it does provide significant information about how you approach your world.
It's very easy to put together some sentences with keywords from each sign that allows you to uncover anyone's cosmic trinity. I'll use myself as an example to illustrate the simplicity.
My Sun is in Taurus, my Moon is in Sagittarius and I have Aries Rising. Without knowing anything else about my chart, you can surmise the following.
Sun in Taurus: Maria has the energy to be practical, grounded and sensual, and to use her talents to create something lasting. She radiates warmth and vitality when her physical and material security needs are met.
Moon in Sagittarius: Maria has the need to spread her wisdom and to have her philosophy listened to and respected. She needs to teach and learn in order to feel secure and fulfilled. Travel, higher learning and metaphysical pursuits will help her feel nourished.
Aries Rising: The cover of Maria's book is energetic and enthusiastic. She comes across as independent, courageous and pioneering. She shows others that she's a leader and willing to take the initiative in order to express the energy of her Sun sign and fulfill the needs of her Moon sign.
It's that simple! Now, following the same format, I encourage you to do this for yourself and anyone else you're curious about. Find out your own Sun, Moon and Rising signs -- or anyone else's!