Pull that baby forward!! Way too often I see the entire rug hidden by the bed! Typically 2/3 of your rug should be showing at the foot of your bed!
Rug dimension guide:
Full/queen: minimum 5x8 (for bigger size rooms 6x9 or 8x10)
King: minimum 6x9 (for bigger size rooms 8x10 or 9x12)