When you're writing a scene, there are two BIG mistakes you can make with describing stuff.
ONE - You don't describe ANYTHING outside of dialogue. If you fail to describe anything from the setting, it will seem to your reader like your characters are acting against a blank wall.
Mistake TWO - You describe WAY TOO MUCH! If you describe the clock ticking on the wall, the breaking china, the screeching cars outside, the phone ringing, the blaring music and the noise from the other customers, your reader will miss the fact that your main character is trying to ask his friends for help in solving a murder mystery.
So balance what you describe in your writing. Take advantage of describing touch, taste, hearing, taste, and smell. Just make sure you don't describe all of them in one scene!