All pool players know how hard it is to make the 8 ball on the break while playing straight pool.  Unless you get a lucky kick, the 8 ball will stay in the center of the table.  The break described below will give you the best chance of making the 8 ball.

Steps

Place the cue ball about three inches from the rail at the second diamond.
Depending on which rail you placed the cue ball at, use low inside english on the cue ball. This will keep the ball on the table after you break.
Use a steady stroke and hit the ball behind the cue ball. This will break most of the balls away from the 8 ball.

The video below will show how the cue ball should strike the second ball of the rack, not the first.  While you are watching, notice several aspects of this shot; the cue ball going into the side rail after striking the rack and coming back into the center of the table, the 8 ball being knocked down table and hit once by another ball, the power of the shot.

There is no way to make the 8 ball every time on the break, however, using this break will increase your chances as the 8 ball is usually knocked down table by other balls in the rack or hit by the cue ball when it comes off of the rail.