How to Negotiate for a House

This morning I had a conversation with another agent
that was worrying about a floundering round of
negotiations. My suggestion was to simplify the volleying
by asking a few questions.
1.) Are the buyers/sellers legitimately motivated?
2.) What specifically is their motivation?
3.) What are their priorities? (It's not always price -
some people are worried about the closing date, others
are concerned about fraud and liability)

After determining the big 'WHY,' whittle it down to
the current snag, and disregard all other concerns and
comments that are not a part of the written offer.
4.) Why is this item so important, when we've already
conceded on your biggest priority?
5.) Is the item significant enough to risk losing the sale
of entire house, yard, garage, and media center?

NOW you may start negotiation!
6.) Ok, if this is so important, we can all agree that you
may have the abc, if we can retain xyz.

What happens if that doesn't work? Go back to #1.