There, Their, and They're

One of the mistakes that I pick up on commonly is the misuse of There, Their, They're. This deadly trio has tripped up writers of all aptitudes and positions. I've made this mistake more than once in my career, usually in haste. The problem with these words is they're homophonous, and of similar sound and pronunciation with differentiation in meaning.

What is the difference?

There - adverb

1. In or at that place. (opposed to here)
2. At that point in an action, speech, etc. 
3. In that matter, particular, or respect.

examples:

• There is an inherent danger in flying; nevertheless most of the time it is safer than driving.
•  He must stand there in the corner until he apologizes for his rude behavior. 

Their - pronoun

1. A form of the possessive case of they used as an attributive adjective, before a noun.
2. Used with a singular indefinite pronoun or singular noun antecedent in place of the definite masculine his or the definite feminine her.

examples: 

• They left their car lights on, should we let them know?
• It's good for teachers to have high expectations for their students.

They're - contraction

1. The result of contracting or combining the terms they and are.

examples:

• You think they're in there?
• Don't worry, they're tamer than they look.