Show don't Tell

A good writer doesn't tell the reader what's happening, he shows them.

Example:

1. Carl was mad.

-or-

2. Carl's eyes flashed and his mouth turned downward into a tight knot.

The reader learns Carl is mad by the way his facial features are described.

1. A black cat was on the broken fence.

-or-

2. A cat with fur as dark as midnight sat rigidly on the broken wooden fence.

The color of the cat is related to something commonly known, dark as midnight. It's more interesting to read than "black." The reader learns the cat wasn't just on the fence, it was sitting stiffly and the fence was wooden. A clearer picture is created in the reader's mind.