Brown pants can be worn with a white, pink, ecru, light blue or yellow top. White shirts can go with almost any color of pants.
If brown pants have a pattern on them, it is best to wear a shirt in a corresponding color that does not have a pattern. Likewise, if the shirt has a pattern, the pants should not. Pants or shirts with subtle patterns, like herringbone, usually appear to be solid colored and as a result can be paired with a pattern.
To look taller, brown pants can be paired with a shirt that has a similar tone or depth. To look less tall, break up the colors by pairing brown pants with a color such as pink, which does not have the same depth or intensity as most shades of brown.