NOTE: A Basic Golf Swing is now available that develops the comments below in full, and more, in both words and video.
Golf instruction books speak of three orientations of the hands when taking a grip: strong (the Vs between your thumbs and forefingers point outside your trailing shoulder), neutral (the Vs point at your trailing shoulder), and weak (the Vs point at your chin).
These are grip categories, however. They should not be taken as actual ways to set your hands on the club. How you do that is an individual matter that should reflect the natural orientation of your forearms. *
Instructors often talk about the clubface getting out of alignment because the hands turned the clubhead, but they do no such thing because they can’t turn. It is the forearms that turn, carrying the hands with them. This is not a trivial distinction.
When the forearms start out in their natural position, they will stay there (unless you disturb them) and return the clubface to the ball square. If you address the ball with them out of position, they will return to their natural position during the first few feet of takeaway, very likely without your being aware of it. There goes your shot when it has just barely started.
Stand with your arms hanging naturally by your sides. Notice where the backs of your hands are facing. They must face the same way when you put your hands on the club, which in turn puts your forearms in their natural position.
If you have trouble with the clubface being either open all the time at impact, or closed, and have tried everything to fix it without success, consider that the only problem is with your grip. It’s not your grip.
Try this analysis and correction on your own and see if your shots don’t straighten out. The technique described in this earlier post provides extra insurance.
You might find as well that the swing feels kind of effortless because you are not forcing your arms to move in a way they don’t like.
* The only instruction books I have found that mentions this point is the chapter on the grip in Al Geiberger’s book, appropriately titled, Tempo, and Phil Galvano’s Secrets of the Perfect Golf Swing.