With WordPress you can change the look of your site very quickly by choosing a new theme.
Note: Changing your site theme from one theme to another may result in broken links or missing menu items so it is important to check links and menu items to ensure continued functionality. Different themes put the menu and sidebar(s) in different locations resulting in some visual rearranging that may need addressed. Themes also use the header and background images in different ways that may affect the cropping and look of your images.
Theme Examples can be found at WordPress Themes as well as a list of all available plugins and widgets.
Additional settings can be changed in the Appearance menu under “Customize” to personalize everything from the background image to the title of the site and more depending on the particular theme you are using. Be sure to click the [Save & Publish] button when finished to save your edits to the site’s appearance. Some themes also house additional theme specific settings here such as specialized post layouts or slideshows.