Traffic-Boosting SEO Backlinks

My goal is to grow overall website traffic through a focused SEO campaign built on authoritative, white-hat backlinks. I already have baseline on-page optimisation in place; what I now need is an off-page push that moves key pages higher in Google and, as a result, sends more qualified visitors... (Budget: $15 - $25 USD, Jobs: Content Marketing, Google Analytics, Internet Marketing, Keyword Research, Link Building, Marketing, SEO, Social Media Marketing)