- Simplify Your Design: Use a simple, clean design to ensure compatibility across all email clients. - Inline CSS: Use inline CSS to make sure styles are applied correctly. - Fallback Fonts: Always provide fallback fonts in case the custom fonts are not supported. - Alt Text for Images: Include alt text for images to ensure the message is conveyed even if images are blocked. - Test Extensively: Regularly test your emails across various clients and devices to identify and fix issues.