This is for those photogs out there who are using some pretty expensive equipment. Particularly cameras with lenses that give you an ability to adjust the macro focus in addition to your regular focus. If you know what I'm talking about, then this is for you.
First, get your subject in focus.
Next, use the macro to blur the object.
Quickly rack the macro back into it's original, locked state and bam! a perfect, quick rack focus.
This isn't for the purist who wouldn't use a rack focus to begin with.
For those who have read this far and have no idea what a rack focus is, it's simply when you bring a an object into focus DURING the shot. It can also be used to switch focus from one object to another. It's often very necessary to use rack focuses and you'll see it a lot in movies.
For those of you who are still shooting on less expensive equipment where you don't have much control over the focus, this is another trick you can look forward to using when you upgrade.