If you've got a chart with dominance in one or two signs, then the quality of those signs will be a major theme, too. Most charts come with a graph at the bottom that shows the breakdown of qualities in a chart.
The qualities are cardinal (Aries, Cancer, Libra, Capricorn), fixed (Taurus, Scorpio, Aquarius, Leo) and mutable (Gemini, Virgo, Sagittarius, Pisces). This is a way of categorizing signs, along with the elements. Both the elements and qualities tell you a lot about a chart; the elements are about temperament, and the qualities are about behavior.
In the beginning, you can keep your analysis of the chart very simple. Start with the Sun sign, and see which quality it's in, then move on to the other planets. Generally, the cardinal signs are initiating, the fixed signs persist in one area, and mutable signs are changeable. The art of interpreting a chart, is seeing with your intuitive eye, how these different modes of behavior come together in one chart (or person's nature).
For example, you might have Mars in a cardinal sign, and this keeps you pushing into new ground. But your Moon might be in a fixed sign, giving you an emotional need for stability. This could make you daring in your career, with the need for a stable, rooted home life or routine.
Taking a look at the qualities, is a first step in chart interpretation. Just hold them loosely in your mind, as you consider all the factors and themes at play. A heavy emphasis in one quality will point to a major theme. Over time, it can explain behavior patterns that keep showing up in your life.