1. Be Descriptive: Clearly describe the content and purpose of the image. 2. Keep It Short: Aim for a concise description that provides enough information without being verbose. 3. Use Keywords: Incorporate relevant keywords naturally to improve SEO and deliverability. 4. Avoid Redundancy: Do not repeat information that is already conveyed through adjacent text. 5. Focus on Functionality: Ensure that the alt text reflects the function of the image, especially for buttons or links.