Most players know the backswing is important, but they should also realize that they can get away with some imperfection in that area. The downswing isn't as accommodating: At impact there is only one clubface angle and path that will produce the desired shot. Here are a few downswing thoughts that might work for you.
Trigger Downswing with Left Ankle

Solid contact and straight
shots come from proper sequencing on the downswing,
which means that it must start from the ground up. One
way to start the downswing is to roll the left ankle
toward the target. Think of this move as the first
domino: The ankle moves the knee, which turns the hip,
which turns the torso, which unwinds the shoulders, and
swings the arms and club into the ball.
Put Your Foot Down

Some players get into a rut
of errant shots -- blocks or pull hooks -- when their
right hip becomes overactive and slides toward the
target, pulling the club off-line. To quiet the right
hip and get the club back on the proper path, focus on
the right foot. Concentrate on keeping it flat on the
ground during the downswing and past impact. Don't let
it roll inward toward the left. Keeping it flat will
keep the right knee slightly bowed out and prevent the
right hip from sliding through too early.
Swing Left Past the Ball

A simple way to shape the
downswing is by working on the follow-through. Some
players tend to develop a swing path that is too far
from the inside, producing blocks and hard-to-control
hooks. If that's you, try this follow-through thought:
Focus on swinging the club left, or more around your
body on the follow-through, rather than out toward the
target. You may feel that your swing will produce a huge
slice, but in reality, the low-and-around follow-through
will keep your club moving down the target line on the
downswing, rather than inside out. A good key is feeling
as if your upper left arm stays married to your chest
until the last moment of the follow-through. As your
torso rotates through the ball, your hands and the club
will naturally move left.
Private Lessons 1999 Time4 Media, Inc., used under license by GolfServ Online, Inc. Instructional information provided by Golf Magazine.