Undoubtedly, the rescue club is the most reliable option when the ball is sitting down in the rough or in a divot.
In this situation I make a simple alteration to my normal swing to ensure that I strike down on the ball, without catching the ground first.
In the address position, set the ball back in your stance (just back from centre) and place slightly more weight on your front foot. These adjustments will alter the angle of your downswing, ensuring a steeper descent into the ball.
My only swing thought is to keep my hands low in the finish position, with a slightly shortened follow-through. This reduces your hand action to minimise the amount of spin generated at impact for a flat, controlled flight.