1. Start with a Mobile-First Approach: Design your email for mobile users first, then scale up for larger screens. 2. Use Inline CSS: Many email clients strip out external CSS, so inline styles are more reliable. 3. Media Queries: Use CSS media queries to apply styles based on screen size. 4. Test Across Devices: Use tools like [Litmus](#) or [Email on Acid](#) to test your email template across various devices and email clients.