The Queen is by much the most powerful of the forces.
Be cautious of playing your Queen in front of your King and in subjecting yourself to a discovered check. It is better when check is given to your King to interpose a man that attacks the checking Piece than with one that does not.
The Bishop and Knight, in contradistinction to the Queen and Rook, are called Minor Pieces.
The Queen is usually reckoned equal, in average situations, to two Rooks and a Pawn, but towards the end of a game she is hardly so valuable as two Rooks.
Be careful, too, when about to capture a distant Pawn or Piece, that you do not remove your Queen too far from the immediate point of action.