Many web developers and agencies have slightly different ways of working when it comes to designing and programming a new website. Some businesses will require a few meetings to find out exactly what it is you want, visuals most of the page templates for the site and get it all agreed before they even start programming it. Others may get a brief description from you and then meet with you throughout the process to make tweaks and changes along the way.
Ideally to ensure you get the site right first time you spend to spend some time talking through ideas and then working out what and how you are going to include in to the site. The best way to do this is to write down all the functionality and pages that are needed on the site then create wire diagram of the main pages to show how it will be laid out and what will be included on each page. You need to button down the main navigation as one of the first things, so you can ensure you have a quick and easy way to access all the main pages of the site. Once you have this you can then create a flat visual based on the information.