Many players go into a backhand stance when blocking. This is fine for the backhand, but it weakens the forehand side. Even worse, it makes smashing or counterlooping on the forehand much more difficult. You may find that you can block backhands almost as easily with a slight forehand stance, which also puts you in a position to block, smash, or counterloop if the ball goes to the forehand. (Also, a forehand stance makes it easier to step around the backhand if you see a weak ball to crush with your forehand.) Try experimenting with this. Many a player has won a match by standing in a forehand stance and just blocking backhands until the ball goes to the forehand, and then Whammo!