These days it seems nearly impossible for new writers to find an agent. Agents, like everyone else involved in publishing, are overwhelmed, bombarded, and don't have enough hours in every day. As a new writer, do you need an agent? It can't hurt, if you can find the right one, which means someone who "gets" you, appreciates your work, vision, voice and potential, and will work like hell for you, which of course only benefits the agent as well.
The best way to look for an agent who will be the right fit? First, do your homework. If you have written a fantasy YA novel, you need to search for agents who handle that particular genre, or might be new to it and thus are actively seeking writers of fantasy YA novels. Proceed to your nearest bookstore, or online book store, or library -- a wonderful resource people often forget in these technologically-driven days -- and find fantasy YA novels you appreciate and respect, and then start tracking down the agent of those writers, which could mean simply reading the author's "acknowledgements" page, where you might just find a "thank you to my editor" with a name included, or more labor-intensive efforts, such as contacting a book's publisher and tracking down names that way.
Once you have an agent's, or a few agents' names, find out their agency's submission procedures and then follow those assiduously. Trying to be clever, creative, and a "stand out" when first contacting an agent will backfire, if you fail to follow, to the letter, the agent's submission directives.
There are also contests that allow writers to submit samples of their work that may involve agents as judges. For example, Writers Digest, through its Guide to Literary Agents blog by Chuck Sambuchino, is hosting its 23rd “Dear Lucky Agent” Contest," a free recurring online contest with agent judges, focused on a specific category. The 23rd contest is for anyone writing a middle grade novel. You submit the requisite number of words, follow a few other directives -- and remember, always follow directions! -- and you will be part of the contest, which is live through end of day, September 19, 2016. Here's the contest link: