I should be reading, but I wanted to pop on here for a minute because I just remembered another piece of advice I wanted to give to any unagented authors out there who are trying to get their book published.
Unless the publisher or the editor's submission guidelines specifically say they will only take exclusive submissions, DO NOT send them your submission exclusively!
Now, I believe this is different for agents, so don't carry it over to the other side of querying, but this is something I saw recently and it shocked me. Sending an editor an exclusive submission when it's not required is unfair to you. It's a major time suck. Why should you sit around waiting for me to get around to reading your project, all the while not sending it to other editors who might read it faster? Especially if you're sending to editors at a company like mine, that works mainly with agented submissions and only takes unagented submissions under special circumstances (see previous posts). Oftentimes, you're going to have to wait for us to get through a decent amount of the agented stuff before we can legitimately get to yours, and why should you wait for us?
In my opinion, only an agent should be sending exclusive submissions. They have a relationship with the editors, so they know who will love what and will give them an exclusive because they want that project with that editor and think they will love the project enough to potentially make a swift and solid offer. They have easy access to that editor for following up, and they know the industry well enough to give a reasonable amount of exclusivity (two weeks, sometimes one).
So if you're sending your project out to publishers and it's not required, don't send exclusively. Because when you get interest or an offer from an editor at one house, that will give you leverage to follow up with the other editors who are taking their time and let them know there is a reason to hurry up and respond, and they may give you a higher offer. They may still decline, but they would've anyway and now you have your answer quicker, as well as interest or an offer from a house that actually got back to you within a reasonable amount of time.
And again, agents are different. Maybe one of them can comment on this post and explain why this is and how submitting to agents in regards to this.