True outdoor furniture is manufactured to resist the rigors of radical temperature fluctuations and the onslaught of moisture. Although some of these durable pieces are better suited for covered areas, such as porches or gazebos, many deck products now are made to withstand direct exposure to the elements.
Arrange furniture for your deck just as you would any room. Create groupings for various activities. Place seating close enough for easy conversation, but not so close as to invade personal space. Allow for traffic to flow easily between furniture groupings.