Publishing is a dog eat dog world. Most publishing houses (though not all) will not even consider an unagented submission. Those that are willing to take a look are much less likely to offer a contract to an unagented author over an agent. There are a few reasons for this.
First of all, an agent knows the ins and outs of the business. They know what publishing houses are looking for in quality. They are familiar with contracts from the companies. They even know certain editors by name, personally, and know how to approach them and what sort of book the editor is looking for. Basically, an agent cuts the hassel out of the publishing process for both the publisher and the agent.
Unagented authors really have no idea how to approach a publisher. This makes it less likely that someone without an agent will get to a contract than someone with an agent. That’s not to say that unagented authors won’t get them. It does happen! Don’t let it discourage you. However, if you are going to approach without an agent make sure you do your homework. Know that publisher, that editor, backward and forward.
So you want to improve your chances by finding an agent. Great! Now you have to undertake the task of finding agents looking for your work. In this, the internet is your best friend. There are several good resources out there. The Guide to Literary Agents is a great place to start. They list new agents, agents starting their own business, and much more. All of the agents listed are reputable ones, members of the AAR (Association of Author Representatives) which is highly important. That means these agents are not scam artists!
Writers Market is an invaluable resource. This does require a membership if you look online. Otherwise, try your local library and seek out the latest edition of Writers Market books. Obviously the online resource will be more up to date than the book, but if money is an issue, the book is a good place to start a list. Then go back to the internet and look up each of the agents you are interested in to find out what they are looking for, if they are open to submissions, and how they want you to submit.
I can’t stress this enough. Go back to the internet and look up each individual agents requirements and wants. It will do you no good to submit to an agent that doesn’t look at your particular style of fantasy. Check out a couple of books they have represented to get a feel for what they are interested in.