Don't use it when the direct object is an inanimate object.
This preposition is called the personal a because we only use it when referring to human beings! With any other direct object, it's totally superfluous. Compare these two sentences: Yo veo a una chica.
JUST GIVE ME POINTS ITS NOT HARD
1. Me 2. Te 3. Le 4. Le 5. Les 6. Nos
Lo necesitas en ingles?
Linda is visiting New York with her friend and is writing this letter to her family.