Search Engine Optimization is a very involved process, which requires all elements to work in tandem, and all elements to possess originality. I'll try to break down the basic 7, although there are 21, main areas to look at when optimizing your website.
The main areas of importance for fundamentally good SEO are: Back links, content, keyword-centric title tags/meta/H1's, Don't use javascript for page content, Don't use frames, Don't hide text, and Don't copy or present any duplicate text.
Build your Back-Links
These are links into your site from external sites.
Content is King
Truly the most important aspect of the Search Engine Optimization process.
Title/Meta/H1 Tags
Title tags are one of the three most important facets of search engine optimization.
Don't use Java to generate Content
Any content provided by javascript is not indexed. Look at your source code - whatever is there is what will be indexed.
Don't Use Frames
The content becomes hidden with frames, and search engines will not index it.
Don't Hide Text
You might think you're clever to put text over same colored backgrounds. You're not.
Don't hide text or make it too small. Simple rule, if humans cant read it, SE's won't either.
Don't Duplicate Content
This should be obvious, but if you thought about copying your content from somewhere, or hosting multiple copies of one article - Don't.
So, essentially the fundamentals of the first 7 factors of SEO are: Back links, content, keyword-centric title tags/meta/H1's, Don't use javascript for page content, Don't use frames, Don't hide text, and Don't copy or present any duplicate text.
