Since I do mostly nonfiction, I receive a ton of proposals. There are great proposals and there are the ones I call “canned tuna.” These are the ones that give off an odor the minute I open the file. They’re like the one-size-fits-all pantyhose, which is a bunch of malarky because the very idea that a size 0 and size 14 will fit into the same pantyhose is breaking all Newtonian laws and the space/time continuum.
One size does NOT fit all. Nor do proposals.
If you’re querying an agent or editor who specializes in a particular theme, then it’s smart business to play up those themes. For instance, we’re all about socially relevant personal journeys. You may have a very cool memoir that will put the jam in my jelly doughnut. But if it doesn’t showcase those socially relevant elements, then I will probably have to take a pass ‘cos you didn’t bring them to the forefront. Let’s say your memoir as a champion belly button beauty contest winner has socially relevant characteristics of “beauty is more than bellybutton-deep.” You would be nuts not to highlight that when querying me. All agents and editors are looking for a larger hook than simply a hot-looking bellybutton and since we aren’t familiar with your work, it’s your job, as the architect, to build us a solid foundation that includes those hooks.
Many agents and editors have a particular focus, and the proposal is your sales pitch. You want to include every facet that scratches the editor’s/agent’s literary itch.
And this brings me to tailoring your pitch – whether it’s a 35 page proposal or a query. Anyone who advertises their focus on a particular issue is looking for the author who tailors their pitch to scratch their itch. It isn’t canned tuna. It’s freshly caught and cooked just the way we like it. If we want cream sauce, then you provided it. If we want capers (which are God’s secret flavor bombs), then you toss those in as well. You make that tuna taste exactly to order, and this makes us want more.
Sure, tailoring a query or proposal is more work, but it can be the difference between “send pages, please,” or “no thanks.”
It’s professional and impresses the one receiving your work. It says, “I have researched your company and know exactly what you’re looking for. I respect you AND care enough about my work to help you understand the unique qualities of my work that fit in with your house.”
I can smell “canned tuna” from ten paces.
If you want the inside scoop on what floats our boats, 
