Question from a beginning lead.

The steps going into a quarter turn and a grapevine are very similar - slow, slow to outside partner, then you can continue with either the quarter turn or the grapevine but what is the clear, unmistakeable lead cue to either step? My partner is having trouble reading my mind so I'm looking for a more reliable method. Thanks.

That's a great question, and I also look forward to hearing from the instructors and experienced dancers in how they answer this.
I also have some trouble in making sure my partner knows when we are going to any steps that unfold outside partner, which is where most of the interesting, fun and classy steps take place in my opinion.
I would love to know some fail-safe triggers, other than whispering "Grapevine," or "Continuity Styling" or "Shadow Twinkles" when we are moving into more advanced steps. The Fox Trot seems to pose the most trouble in this regard, whereas in a dance like the Rumba, it seems the transition to more advanced steps fit right into place. Is that it? That the Fox Trot moves in LOD, whereas Rumba is more stationary?
Thanks for the question, molesaver.

They are not remotely similar IF you commence it from a Silver twinkle .