What is needed in your queries is only your experience in writing long fiction and not that in writing scripts, poetry or any journalistic endeavors. If this is your first novel, ever, state that and only that in your query. If you have written other novels but they are not the ones you are querying on, please mention them.** We realize that many writer boards advise members to list all writing experience in your query letters, but this agency thinks it a waste of time and effort. It means nothing to us as we judge your ability on your writing sample(s) only and not what you say about yourself. We cannot use this information to impress editors, consequently, for us, it is meaningless and unnecessary information.
We are not saying here that a journalist cannot become a novelist. Many famous novelists could do both quite well. We are only saying that adding this to a query letter is more information than we need to evaluate your work, and it could distract from other important ideas in your letter.
Focus is critical in a query! You need to concentrate on what you want to get across to your reader (the agent or editor), just as in a cover letter for a resume you need to focus on narrowly defining the skills and projects that fit the job for which you are applying. The same is true in querying on long fiction.
**However, keep in mind that if you have written seventeen novels and have yet to place one, that might not look so good. If you have written seventeen novels and you just now feel that your work is ready for publication, then make sure that comes across. Don’t let the message in your query come out as, “I can’t get published and I don’t know why, but I just keep writing new stuff.”