The Domain Name
Page Titles
Meta Descriptions are Unique
Meta Tags
URL Structure
Body Tags (H1, H2, H3, H4, etc.)
Internal Linking

The best on-page factors are:
1. Title Tags
2. URL Structure
3. Meta Description
4. Meta Keywords
5. Alt Tags
6. Internal Links
7. External Links
8. Understanding Sitemaps

1. Content comes first
2. Page titles, description and formatting
3. URL Structure
4. Internal linking
5. Speed and authorship

Best page factor are:
Keyword research
Page title
Url structure

Thanks for discussing this useful details

Meta tag
URL
Sitemap
Robots
canonical etc

On Page Factors
1. Metadata
2. Sitemap(xml,html)
3. Robots.txt
4. Alt tag
5. Google Analytic
6. Google Webmaster

Best On Page Factors :-
Target Keywords
Meta Attributes
Contextual Content
Internal Links
Quality Content
Content of Page
Good content supplies a demand
Good content is linkable
Title Tag
URL
SEO Best Practice