Several factors can affect SEO. These include the quality of your content, user experience on your site, site speed, mobile-friendliness, secure and accessible website, domain authority, page optimization, technical SEO, social signals, and the effectiveness of your link building efforts. Also, staying up-to-date with Google’s algorithm updates can significantly impact your SEO efforts. So, it’s crucial to have a comprehensive, strategic approach to SEO that considers all these important factors.