Let’s face it, folks. We all make mistakes. Try not to make these! Do not include:
Any kind of apology.
Any kind of excuse for your writing.
Any statement that makes you sound like an amateur (even if you are!).
More than one idea at a time.
An explanation of why you don’t have any published works. (If you don’t have any, don’t mention it at all!)
The entire piece if they've specifically asked for a query letter only.
Another piece you’ve written that has no relevance.
Another piece you’ve written that hasn’t been published.
A statement that you’re sending your idea to somebody else as well.
A long story about how you’ve always wanted to be a writer.
Personal (and therefore, irrelevant!) stories about your kids, friends, family, or dog. Remember, this is a business letter, and the editor has no time for that which is not part of the business.
A phone call to pitch your idea.
An idea with no backbone and no research behind it.
An idea that is too general, such as “Having a Baby.”
A recommendation from your friend, mom, boss, brother, or whomever telling the editor how great your writing is.
Complications. An example of this would be giving your current address and the address where you’ll be moving in a month. Just wait and send it in a month.