The degree to which a script has to be truly ready before submitting to producers and agents was brought home to me several years ago in a rather vivid and unforgettable way. 
The professional theatre I founded and ran for many years, Playwrights Theatre of New Jersey, was awarded a large foundation grant of over two hundred thousand dollars to sponsor and conduct a major national playwriting contest.  Our goal was to find the two best new American full-length plays, award each of the two playwrights a $10,000 cash prize (then by far the largest cash prize in the country), and produce professional public workshops of both plays with the playwrights involved every step of the way–from having a voice in choosing the director to casting in New York City under the guidance of our experienced casting director.  In addition we were offering each winner a dramaturg and production designer to be a part of the workshop experience. Suffice it to say, this was a playwright’s dream prize—a large cash award and a chance to have their play workshopped before an audience in a highly professional way.
With this all in place, we set about getting the word out about the competition, advertising widely in every writer’s journal and newsletter we could find.  We had a five month window for submissions and our marketing was relentless, saturating every conceivable channel where writers might see mention of our competition. 
By the submission deadline we’d received 1,007 scripts, a resounding success at least in terms of numbers, given the fact that this was the first time the competition was being offered.  Early on in the submission window timeframe, scripts trickled in.  But by the last couple of weeks, the surprised mailman was literally dragging into our theatre offices huge canvas bags full of scripts.  We were excited, but I must admit there were days we felt quite overwhelmed by the sheer volume of plays stacked before us. 
Anticipating a large number of submissions, we had hired a full-time and very efficient literary manager to carefully log in every submission.  The writer’s name was removed from the script and instead a code “name” was given to each submission so any known writers could not be identified, possibly skewing a script’s evaluation. We also recruited an army of readers, all established professional theatre or film people and trusted colleagues, who were paid generously for doing coverage on each script.
We were determined to bend over backwards to give every submission the benefit of the doubt in our evaluation process.  In the first round, every submission was read by two readers, a short summary and appraisal written, and a rating given on a scale of one to five, with five being the best and one being the worst. We established clear guidelines for each rating category so all readers would be using the same basic criteria for evaluation.  The literary manager then studied all reader reports and an initial determination was made. Generally, if the two readers both gave a script an average rating of two or worse, it was rejected.  But if the average rating was between two and three, then the script was given to a third reader.  All scripts that ended up with an average rating of three or better after two or three reads were considered worthy of continuing on to the semi-finalist round.
This is where things started to get interesting.  What we came up with after going through this careful and arduous evaluation process on 1007 scripts is 33 semi-finalist entries.  That’s it.  33.  Out of 1007.  Or 3.28%.  And this was just the semi-finalist round.
I must admit I was puzzled and a bit shocked by this low number.  So I did some checking of my own, selectively dipping into a number of the scripts that hadn’t made it but were rated between two and three on our evaluation scale.  It didn’t take long to realize that the readers had been doing their job well and that they had found every single script that had a fighting chance. 
The next step was for me and two of my most trusted professional colleagues to read all 33 semi-finalist scripts.  And this was when the true revelation hit me.  As I got deeper and deeper into reading these semi-finalists, I couldn’t believe these scripts that had made it into this second round weren’t stronger than they were.  I actually started to panic at one point, thinking that we were going to be forced to award these huge prizes we’d announced to writers who hadn’t written prize-winning work. 
 In the end, we came up with seven finalists.  Seven.  That’s less than one percent of the total submissions to the contest.  Seven scripts out of 1007 that we felt were in one way or another worthy of being awarded our prizes. We had recruited three well-known theatre and film industry people to be our final judges.  And out of these seven finalists the two winners were chosen. 
The point of all this is obvious.  But the degree to which writers think their work is ready to submit when it isn’t only hit home for me after having gone through this experience from the inside.  So I share it here in the hopes that it helps to give some perspective to where your script may land in the pile and the patience and hard work that must be mustered before it is ever submitted to the powers that be.