How do I use alt tags in my SEO marketing?

Alt tags, also known as alt attributes or alt descriptions, describe images on a website for users who cannot see them, such as those using screen readers. Using descriptive alt tags not only helps with accessibility but also improves SEO by providing search engines with additional information about the image. 
To use alt tags effectively for SEO, include relevant keywords and descriptive phrases that accurately describe the image content. However, avoid keyword stuffing and keep alt tags concise and relevant to the image. Additionally, ensure that alt tags are unique for each image and avoid using generic phrases such as "image" or "photo".