Basically my website Clean Script is valid XHTML/CSS, but I've used nothing buy DIV's, STRONG, EM's and list tags when needed to design my template. What should I do to fix this, I was just reading another article about changing your page completely can hurt your page? Is it changing the content or changing of the HTML that can hurt your page. I want to rewrite my xhtml to use H1 tags and what not. Thanks in advanced.
You will be fine, just don't have dozens of H1 headings per page. Google do look at template code for certain things, but this won't negatively effect what you are doing.