Here is a great drill for speed or learning to draw the golf ball. I see a lot of tour players do this; you can watch it on television. Take the club well above the ground, almost up to waist height, take your normal grip and practice swings above the ground. You should hear a swish. What you have here is no resistance. You can actually start to really get some speed and really pick it up. Plus you will also start to get the rotary motion of your hands, you can not stop it, your club is going to go over so that it really allows your arms to work in a total release fashion. If you are someone who hangs on, blocks and misses shots to the right, or needs more swing speed, practice swinging above the ground. You can do this with your 9-iron, your 5-iron or your driver; you will get a little different feel. When you get to your driver you can really make a loud swish and it is a great drill for anyone that is trying to build more speed into their golf swing.
Jim McLean runs the Jim McLean Golf Schools, considered by some the world's finest. He is listed as one of Golf Magazine's Top 100 Teachers and Golf Digest's #3 instructor in the world.