Almost ALWAYS! Query letters are standard in the industry. That being said, what is most imperative is that you do your homework when approaching any agent. They each have a preferred method of submitting work to them. Most of them begin with a query letter. That being said, what makes a successful query letter? In my experience, a great query letter is often not written as much as it is arrived at. I usually write a pretty good first draft, but don’t really find that my query letters are working until around the sixth draft. Remember that the goal of the query letter is to get an agent to request additional material. So determining the quality of the query letter is done relative to the number of positive responses. If no one is asking for your material, look to the content of the query – specifically the following:
1. Very short personal and professional intro that demonstrates that you are not just mass emailing agents.
2. An exceptional logline. One or two sentences at most that combine your protagonist’s goals, motivation, external conflict, internal conflict and the setting of the story to create an awe inspiring reaction.
3. Your credentials – a BRIEF explanation of why you are qualified to write this book.
4. A succinct and professional ending to your letter.
In this equation it is the logline that agents care about most. If that does not inspire them, then the remainder of the query letter becomes irrelevant. Does your query capture the conflict? Does it activate the imagination and inspire images in the mind of the reader? For most people, that is a tough question because by the time you are writing your query, you probably have very little objectivity around your story. So test your query. Create a small focus group. Ask them what images come to mind if any. Ask them if they would want to read that book based on the logline. Ask them if it had them at the edge of their seat. Anything short of that, and you’re not there yet!
All of this being said, the average writer will send out 100 queries before finally getting represented. So hang in there. Revise until your query works. And then stick with it once it does. The focus then will move to the quality of the manuscript.