This is a very short post but I think something this important warrants it. This is something you always need to be aware of when you're learning how players do things.
I read a new Golf Digest article from Dustin Johnson about playing drives and approach shots. For the most part, it's a very good article... but take a look at this photo from it:
In the section of the article about hitting short irons, DJ says "I play the ball in roughly the same spot for each club, centered between my feet." But take a really good look at the photo (you can see it in other photos in the article as well).
The ball is NOT centered between his feet. I suppose it might look that way to him when he's looking straight down from above, but it's NOT centered between his feet. It's close to being centered between his TOES, but you measure the center of your stance from your HEELS.
DJ actually plays the ball slightly ahead of the center of his stance. This allows his downswing to shallow out ever so slightly, even though he's still hitting down. If the ball was actually in the center of his stance, the sharper downward angle of attack would affect his ability to control his ball's distance as well as he does.
My point here is that you need to make sure you study any instructional articles, photos and videos very carefully. Although there's a great deal of useful information to be had -- as there is in this article from DJ -- sometimes small things slip through the editing process. And sometimes those small things can keep you from getting the proper results.