Can you tell me what happens when you receive my manuscript? Do you have a first reader that sifts through all the manuscripts and then passes on his/her picks to you? When does a manuscript go to outside readers? Do all publishers use committees to decide the fate of a manuscript? Who has the final say? Do you follow the same procedure with all manuscripts?
I have an assistant who does a pre-read and sorts them into piles--ones I will probably want to read and ones that I will probably reject. We've worked together for a long time, so she's pretty accurate at guessing what my response will be. If she really likes something, I put it at the top of the pile.
I go through the rejection pile first because those are pretty obvious and there's no need to keep those authors waiting. I write my own rejection letters--most of them are form letters, but sometimes I offer suggestions on what to improve.
The manuscript goes to outside readers if the in-house staff likes it enough to consider publishing it. We need to make sure it will appeal to a fairly wide spectrum of readers.
If they're smart, publishers have some type of committee giving them input. Who is on that committee depends on the size of the company. It may be the readers or it may be a group of employees, or it may be an official committee which includes the finance and marketing departments.
Who has the final say? Depends on the company. It could be the head editor, the president, the marketing VP, or a majority vote of the committee. In my company, it's usually a unanimous vote of the committee.
We follow the same procedure 99% of the time. Sometimes we'll publish something that has a majority vote, but not very often.