Not to steal your thunder ZiGzAg, but here is a slight modification to your holding out the hand, that I use, and really like:
Hold out your hand (in a handshake position), pause a second and say, "Come here, and nod towards where you are going to take her).
If she gives you her hand great.
If she takes a step towards you, quickly put your outstretched hand around her waist or take the inside of her elbow. If she looks nervous, you just retract your hand a little bit, to her mid back, and then use it to "guide" her to the destination.
If she doesn't come, or she looks nervous, just motion with the outstretched hand in the direction you want to go and say, "Come on!" Then you head off to wherever without looking back.
This works well because you are never at a point when you are giving her an ultimatum. Also, it makes it easy for her to allow you to put your arm around her, without it being awkward for either of you.