Ready for another one?
Query Hint #3: Write the first draft of your query before you write your book. Or, if you're already half-way through, write it NOW. Don't wait.
Why would I give you this advice? Because the further you get into your story, the more details there will be in your head, and the harder it's going to be to whittle all those subplots and character arcs and everything else into two paragraphs. When you first think of the idea for your book, trying writing it out as a query. This will not only help you decide what your hook is, what the voice is, what the conflict is, and how to summarize it quickly; it will make your job ten times easier when you come back to the query when you're done and ready to start sending it out. So write it out, and then set it aside.
If you're already writing your book, take an hour or two and write out the query now.
Then, once you are done with your book, go back to that query. You will definitely find yourself revising it. Especially if you ended up having your plot go a different direction than you thought, or if your MC's voice didn't come out quite how you expected. If you already have that early version of your query done though, you will have a great way to gage if you accomplished what you set out to do, and will have less work to do trying to squash your 70,000+ word mss into two paragraphs.
This will also help you to be able to see if you accomplished both hints #1 and #2: does your query pitch what you're claiming to be pitching? and does it show your MCs voice? (And did your manuscript end up doing those same things?)
So, no matter what stage you're at in your manuscript, don't put it off any longer. Go write the query now. And if you have a new idea bouncing around your head, go see how a query pitch for it turns out on paper. Even if you completely change your query in the end, doing that in the beginning can really help you figure out what you hope to accomplish with the next manuscript you are going to write.