There is no perfect designer that makes no mistakes. Review all your web pages to make sure all the links are working, 404 page, robot.txt, sitemap are all in place, check if you incorporate the title tag for your links etc.
SEO Tip of the Day: Title, Keyword, Description Tag
Make sure to incorporate title, keyword and description meta tag into every single page on your site. Use keywords and description that relevant to your page.
SEO Tip of the Day: Use Keyword in Your Image
You can always use keywords as the title of the image. This way not just improves the visibility of your images but also increase the keyword density in your page.