Visitors on your site can help you to get more free traffic.
But to get them to this for you, make it KISS [Keep it Stupid Simple].

One thing users do on a webpage is Add to Favorites. Which result in repeat visitors.
So to make it easy, place a Button there, saying like this,,,, You like the page? Add it your favorites.

This will somehow help to get repeat visitors, not sure how much but it will.