Testing your site's responsiveness is only the first step. To ensure a consistent and satisfying user experience, you also need to optimize your site for different devices and browsers. To do this, use a responsive framework or template that adapts to different screen sizes and resolutions automatically, such as Bootstrap, Foundation, or WordPress themes. Additionally, you can use media queries and breakpoints to adjust the layout, content, and functionality of your site according to the device and browser width. Additionally, use relative units and flexible grids to make your site scale proportionally and avoid horizontal scrolling. When it comes to images and videos, use responsive versions that resize and load according to the device and browser dimensions and capabilities. Finally, make sure you're using web fonts and icons that are compatible with different devices and browsers and load quickly.