Tour Professionals tend to have a 3 to 1 ratio of backswing to forward swing. The biggest problem I see from higher handicap players is there ratio is almost 1 to 1, meaning they are trying to swing the club back as fast as the do going forward.
Without spending money on a swing speed gage the best way I try to describe it to people is how fast do you windup to throw a ball. Do you windup really fast or do you windup gradually building momentum?
Most people windup gradually and buildup momentum to throw the ball. You want to have the same concept for swinging a golf club. Your backswing is a way to build up speed/momentum to bring the club forward.
Practice using different speeds on your backswing and find out where you are most efficient. Try and make the backswing feel fluid and balanced, this should help to deliver the club to the ball more consistently.