How to close a short sale

I see many blogs on the heartache and headaches of short sales, but we are closing deals, we have not had a fall out this year.  It seems the best stratagy is to never take no for an answer, agressive follow up, if you don't like the answer, tell them.  The most important part of the equation, cooperative sellers.  When the provide what you ask for in a timely manner the quicker the deal goes.