[officialtony]

If you make a " clear and strong call every time ", you are , in fact, " selling " your call. That is the philosophy of selling a call. It isn't about dancing or jumping up and down or any of the antics that some guys profess is their way of selling a call. There are umpires ( officials ) who are half hearted about calls they make and this gives the impression of indecision. Indecision is the invitation fans/spectators look for to get on an official. But your " clear and strong " call is a deterent to negative fan/spectator rebuttal of your call. By being clear and strong you give no indication you have any doubts about your call.
Therefore, you have aleady " sold " your call.
Don't underestimate the value of selling the call either. I had two close plays at the plate two nights ago. Both runners sliding under the tag to get a foot on the plate before they were tagged by the catcher. I signalled and made my " strong and clear " safe call with a finger point to the plate stating ( very loudly but firmly ) " he hit the plate before the tag ". I recieved very little grief from anyone on either call ( of course there is always one " official " in the stands who saw it better than I did. ) And I believe that was because I " sold " the call.
Just my humble opinion.