My Grandmother always use to say that a lady should be able to tie a tie for a gentleman and always have an extra handkerchief in her hand bag incase her fellow lost his pocket square. My Grandmother tied my Grandfathers tie on him every morning they were together until he died (it was just part of their ritual). She taught me how to tie a tie and I can't tell you how many times I have helped gentlemen friends of mine tie a proper Windsor knot. Seeing as this first bit of advice has served me well, maybe I should carry a pocket square in my bag (it looks like they are making a comeback!)
Sara