The Personal A in Spanish

Use of the personal a is unique to Spanish and is not included when translating into English (or another language). It is only used to refer to a person, and can be thought of as a more respectful way to acknowledge another person - that is to say that an individual is more important (to you) than say their house.

Por ejemplo:
Yo amo a Lucy - I love Lucy
Yo amo la casa de Lucy - I love Lucy's house.
Buscó a mi hermanas - He looked for my sisters.
Miramos a Jorge lugar fútbol - we watch George play football.
Miramos una película anoche - we watched a movie last night.

Excepciones:
Spanish does not use the personal a with the verbs ser (to be), tener (to have), or hay (there is, are):
Jose es columbiano - Joe is Columbian.
Tengo tres tios - I have three uncles.
Hay una chica en la casa - There is a girl in the house.

You do not use a persoanl a when the direct object is an unspecified person:
Espero un amigo bueno - I'm waiting for a good friend.
Necesito un trabajador concienzudo para ayudarme - I need a hard worker to help me.