Quick thinking is necessary to successful sales.  To be quick, think of all the situations that may arise before the meeting and think of ways you can be prepared to react.

Years ago, a young office sales professional assisted me in teaching sales.  He always took pride in helping me demonstrate the importance of evidence in the sales process.  Each class he would take out the product he sold, compact voice recorders, and demonstrate their ability to survive getting beaten up.  Class after class he would throw the recorder to the ground and the unit never broke.  Finally, it did.  Instead of being embarrassed and lost for words, he quickly responded “The warranty will cover you should this ever happen to you or members of your staff.”  Just his ability to maintain himself and make light of the situation, versus being upset, made it possible for him to maintain control.  He sold quite a few recorders to participants of the class.

What could happen to you in the sales process that would “break” other sales people?

“Things alter for the worse spontaneously, if they be not altered for the better designedly.” 
-Francis Bacon