Agents can tell immediately if a writer knows how to write from the first page of their novel. So bring a copy of that first page, or even the first chapter, to give to an agent/editor if they ask for it. Also, have a copy of your proposal and a short synopsis available. Although there’s no certainty that anyone will ask to see it, it’s always a good idea to come prepared.
Come prepared to talk about your book. Make sure the title is compelling and the book impacts its target audience. Be prepared to tell them about any writing, media and/or professional experience you have as well as how you will be able to do to promote the book. In addition to writing skills and any experience or qualifications you may have, today’s agents look at social media presence to help determine if they would like to take a risk on you/your book. Finally, have a sample chapter(s) and synopsis ready just in case they ask for it.