Analytics are the heart of SEO. As Peter Drucker, Robert Kaplan, and millions of others have said, "If you can't measure it, you can't manage it." For SEO, to say that is almost redundant. (Technically, it would be a tautology. I apologize, but I have 2 degrees in professional writing so these things matter to me.)
What I'm trying to say is that from a certain basic perspective, there is nothing more to SEO than managing the numbers you get from Google. Visits, bounces, average times, segmentation, and so forth - that's all that matters. As you might guess, I have different ideas, but this is not the blog post to get into it. Instead, a quick shakedown on how to get rolling with Google analytics with a Drupal site.