On Page SEO Elements

High value:
Title
Root domain
Body text (without keyword stuffing)

Moderate value:
meta description (for users to read)
URL path
URL filename
Alt attribute
Image filename

Low value:
Outbound anchor text
H1, H2, H3
URL parameters
Text in bold

No value:
Meta keywords (the only people looking at this are your competitors!)
HTML comment
CSS styles