"The farther you hit the ball the easier this game gets..."  - Hank Haney, Golf Digests top 5 teaching professional and former PGA teacher of the year. 

One way to ensure this is by strength training with the Torc Swingtrainer.  The Torc acts as a free weight and can be used to condition golf muscles as well as build a more powerful golf  swing.

The first exercise consists of placing the Torc just above the clubhead of your longest club.  Preferably a driver, but a wood or long iron would work also.  Address yourself as you would on the tee box and take a few swings.  Notice the increase of weight in the clubhead.  Always follow through with your swing and continue with your back swing past your address point and to the top of the swing.  Repeat several times creating a large arc, back and forth feeling the stretch at both the top of your swing and the follow through.  As you continue, allow yourself to increase the distance between your top of the swing and the follow through.  After a few reps of this, you will find this to be a great way to condition and strengthen your golf swing.

The next exercise is more of a bodybuilders approach to building strong golf muscles.  You begin with the Torc at the lowest point of your driver and take long powerful strokes from the top of the swing through and stopping at your follow through.  Hold your position for a second or two and repeat.  This exercise helps build golf specific muscles and will also condition yourself to prevent fatigue during those long rounds.

With just 1-2 minutes a day jumping between the two strength training exercises will get you a stronger more powerful swing.