One without other canot win.
Onpage is necessary for SE to find your site on searched phrasses. You simply need to write useful information for your customers and dont write general offtopic things.
Offpage is about your site importance - google determines how your site is valuable according to the quality and number of backlinks your website have. Google assume quality sites are being linked by its visitors.
Example SEO techniques:
what-is-latest-seo-technique-in-market-t2536.html