The trick to good Search Engine Optimisation is to forget about search engines and focus on visitors.
Make your site clean, clear and to the point. Use proper HTML coding practices. Ensure that each page has a relevant title, relevant description, relevant keywords and original content.
Give each image an alternative text and a title. Highlight important texts in bold or italics.
Have an easy to understand navigation system as well as a sitemap.
In general, keep it simple for the visitor to use and understand. Make it the kind of site people will want to visit to get answers and the search engines will want to rank your site more highly.
There is a lot of talk about back links. These are links to your site from others. These are important to search engines and they will come if you create the type of site talked about here.
You should also find out how to create a popular optimised website.