which On page SEO is most efficient to get more traffic on a website?
 

Yes, On-page seo is very important for Rank any keyword.
some of methods are very important aspects for on page seo like keywords research, meta tags, sitemapping, robots file etc, so which is most effective aspect for seo on website.

SEO and continuously improve your organic traffic, you have to analyze all your site's backlinks and compare their value. Once identified your best backlinks, try to get more of the same.

Although all On-Page SEO factors are very important to get traffic and ranking on search engine, in my opinion, the most important is Title tag. It's the tag which shown in the SERPs as your website title. It helps people to decide whether to click on the listing or not.