Complex sentence: She appeared in her first feature film, "The Dawning," in 1988 and then starred in David Mamet's plays and films, beginning with the movie "Homicide" and the play "Oleanna", a part Mamet wrote for her.
Split into simpler sentences: She appeared in her first feature film, "The Dawning," in 1988. Then she concentrated on her acting career, starring in David Mamet's plays and films, beginning with the movie "Homicide" and the play "Oleanna", a part Mamet wrote for her.