I'll go the other way on this....I've always done best by moving in quickly and taking the shot IF IT PRESENTS ITSELF. If it doesn't or you spook em, back out and circle around in front ofthem and try again. IME, the longer you are there the better chance they have of smelling you.
So, spot them, get the wind, move in and shoot! It doesn't hurt to make a little noise as if they're in a group, they won't pay mch attention to shuffling. You can't break a limb or anything but a little crunching won't hurt a thing.