In chart readings, I look at the position of all the planets at the time of a person’s birth, which makes up a person’s birthchart. Some “planets” (in quotes because a few aren’t technically, scientifically planets, but are referred to that way in astrology) have more of an influence than others, like the Sun, Moon, Mercury, Venus and Mars. Once you get to the bigger aand more distant planets (which move more and more slowly through the signs), I tend to think their influence in a person’s chart is less.
Another interesting thing to look at is the ascendant, or rising sign, which I think of as the secondary Sun sign in a way. For those who aren’t familiar with astrology and its terms, whatever sign you look up in the newspaper to check a simple horoscope is your Sun sign. So, if some guy comes up to me and says, “hey baby, what’s your sign?” and I answer that it’s Aquarius, that’s a Sun sign.