It's not all Astrophysics!
There are some basics in improving your search engine rankings. The first thing to understand is that your website has to be designed well or it won't be indexed well by any of the search engines. You have to make that easy for them. The second thing to understand is that delivering good content is the key to everything else. If you don't deliver great content, it doesn't matter how well you have designed everything else. There is no way to maintain a top search page ranking if your are not generating traffic, and the only way that can happen, over time, is with outstanding content.
The foundation of good SEO design begins with clearly identifying the "key" words and terms that are relevant to your particular business, and then integrating those desired attributes into your website by making full use of the HTML language to highlight these identifiers and make it easy for the search engines to index you website or app into their databases. There is much more to the process than key words and and good HTML.