My advice was always this.
1) Write something good. (With thanks and credit to my writing inspiration, Bill Roorbach. Please click the link and memorize every word.)
2) Set the writing aside and start researching. Look up every book that is in any way similar to your idea, and note the following: title, author, publisher, date. Then flip to the thank you section and note any editorial or literary agent acknowledgements. If you say (with a dramatic flourish) "there's nothing out there like my book," this is very, very bad. It is bad because really? There are no nonfiction/fiction/poetry/memoir books out there? If you can't identify a list of competing titles, how do you expect an agent to sell your book? On what basis would an editor buy it? As an author with zero sales history, you need to present a well-researched pitch.
3) Once you have your list of competing titles, read them. Read them for craft. Pay attention to how the author created the book and note how you might craft yours better.
4) Take your piece of good writing, and improve it. This goes for everything: titles (you should see trends in your list of titles), content, structure, and style. Good writers are good readers. Learn from your writer-peers. Get others to give you honest feedback, ideally people in your targeted reading demographic.
5) Use the information compiled from your list of competing titles to create a short list of editors and agents to contact. You could just send your work blindly from a random directory, but think about it from the professional's perspective: which is the more compelling argument? "Based on your interest in [insert titles and authors], you may be interested in my project. Here is how it differs/is similar in a way that would appeal to the same readership market. May I send it to you for consideration?" Or the other, "All my friends say this should be published."
In other words, writing is work. Treat it as such. Be professional, create a good product, know the market, network, cultivate relationships, and realize that it takes time to build a business.
Inspiration is for amateurs.