Avoid introducing a scene with a block of description that halts the action. Let your character react to the setting rather than see the setting. If you scatter your details throughout a scene, the reader won't be overwhelmed or bored by them. Keep in mind that different characters will perceive the same things in very different ways. Always take your character's educational background, experience and feelings into account.
Mood can also play a critical role.
If your character has had a bad day he or she might perceive their surroundings in a negative light. It is also key to describe settings through your character's senses. Decisions and action are often based on visual information. Hearing induces emotional response. Smell typically evokes memories.