Querying is hard to do, harder to do well, and impossible to do perfectly. Seriously. I've read virtually everything on querying available online, I've been doing this looking-for-an-agent business a while (six-plus months), and I've had my query critiqued to the core by fellow authors. Because of this, I have what is considered a "successful" query, meaning I have over a 25% request rate.
Do I still get rejections? Yes. All the freaking time.
Here a few basic tips that'll (hopefully!) reduce your rejection rate if taken to heart. Keep in mind, I am no expert. I'm just a guy who's been doing this a while.
•Query is spelled Q-U-E-R-Y. If you get this wrong, you should not be querying.
•Limit your query to one page (on Word).
•Agents' guidelines differ, so look at them first. However, the general format is a hook followed by one (or possibly two) paragraphs about your novel, and then your novel's info.
—•Hook: keep it short, sweet, and catchy. Introduce the main character(s) and their struggles. (Struggles is a funny word, don't you think?)
—•About the novel: be sure to include the main characters, their goals, what's keeping them from their goals, and what will happen if they don't reach their goals.
—•Housekeeping: use this format or play with it a little: "_______ is a xx,000..." (round to the nearest thousand) "...word (genre)." Be sure to say it's YA or MG if it is.
—•Bio (if applicable): can be the same paragraph as your housekeeping. Include PERTINENT publishing credits and a PERTINENT degree, if you have those things.
—•"Thank you for your time and consideration."
•Make us care about the characters, but paragraphs of "Sally is nice with long brown hair. Shaniqua is ghetto fabulous." are no-nos. (Unless you plan of juxtaposing Sally and Shaniqua and this is a plot point)
•Do not give away your novel's ending. Stop at a point that makes the agent HAVE to keep reading. Generally, this will be your climax or right before it.
•That said, don't be coy with information. Give us the plot points!
•You do not want to come off as an entitled jerk. Agents enjoy sanity.
•Incorporate voice into your query.
•If an agent asks for sample pages, paste them below the query. Make sure they are the first pages.
•Do not query until your book is complete and as good as you can make it.
Part two coming next week from Amy! In the meanwhile, is there anything we missed or anything you'd like us to cover?