When people think of Search Engine Optimization (SEO), they often want to know how to update their site to get more traffic. They assume that it's a quick fix. If they take the right steps and add some new links or keywords in the right places, then their site will be optimized and traffic will increase indefinitely. It's like creating a software patch. Your lack of SEO is the problem and you need to fix that problem. Once you do, you can just forget about it and expect people to keep finding your newly-upgraded site.
But is this actually how it works? Are you going to get the results that you're after if you do this?