To optimize your Gatsby site on Netlify, consider implementing functional forms with spam-filtering features like honeypot fields or explicit reCAPTCHA, and set up forms with file uploads by creating custom functions to handle attachments. For redirects, use `<a>` tags instead of `<Link>` for URLs that should be handled by Netlify redirects, and make sure to cache content correctly using Cache-Control headers. Additionally, utilize Netlify CMS for managing content, enable service workers by adding a `_headers` file with specific settings, monitor image size and optimize it using plugins like gatsby-image or adjust your use of these plugins, and explore other tips and tricks for building Gatsby sites on Netlify.