These are some tips which can surely make your site SEO friendly:
Don't use Flash (and how to carry on if you extremely must use it)
Don't use frames (and how to carry on if you extremely must use it)
The foundation of the foundation: keyword research
Researched keywords in <title> tag
Researched keywords in URL (file names and folders)
CSS drop down navigation (no Javascript or Flash); CSS style sheets
Density of researched keywords in document text
Don't use hidden text
Researched keywords in anchor text (the text that contains a hyperlink)
Researched keywords in headings <H1>, <H2>, <H3> etc.
Images (including researched keywords in "alt" tags, no text in images)
You can also google the sites which are user and SEO friendly to get some help. For me, Invortex as a whole is a perfect example of SEO and user friendly site.